--- name: "xtrabackup" section: "1" platform: "linux" package: "xtrabackup" version: "9.7.1_rc1-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/xtrabackup" --- # xtrabackup(1) Percona XtraBackup 8.0 Documentation The xtrabackup binary is a compiled C program that is linked with the InnoDB libraries and the standard MySQL client libraries. xtrabackup enables point-in-time backups of InnoDB / XtraDB tables together with the schema definitions, MyISAM tables, and other portions of the server. The InnoDB libraries provide the functionality to apply a log to data files. The MySQL client libraries are used to parse command-line options and configuration file. The tool runs in either --backup or --prepare mode, corresponding to the two main functions it performs. There are several variations on these functions to accomplish different tasks, and there are two less commonly used modes, --stats and --print-param. ## NAME xtrabackup - Percona XtraBackup 8.0 Documentation The *xtrabackup* binary is a compiled C program that is linked with the *InnoDB* libraries and the standard *MySQL* client libraries. *xtrabackup* enables point-in-time backups of *InnoDB* / *XtraDB* tables together with the schema definitions, *MyISAM* tables, and other portions of the server. The *InnoDB* libraries provide the functionality to apply a log to data files. The *MySQL* client libraries are used to parse command-line options and configuration file. The tool runs in either **--backup** or **--prepare** mode, corresponding to the two main functions it performs. There are several variations on these functions to accomplish different tasks, and there are two less commonly used modes, **--stats** and **--print-param**. ## OTHER TYPES OF BACKUPS ### Incremental Backups *xtrabackup* supports incremental backups. It copies only the data that has changed since the last full backup. You can perform many incremental backups between each full backup, so you can set up a backup process such as a full backup once a week and an incremental backup every day, or full backups every day and incremental backups every hour. **NOTE:** Incremental backups on the MyRocks storage engine do not determine if an earlier full backup or incremental backup contains the same files. **Percona XtraBackup** copies all of the MyRocks files each time it takes a backup. Incremental backups work because each InnoDB page (usually 16kb in size) contains a log sequence number, or LSN. The LSN is the system version number for the entire database. Each page's LSN shows how recently it was changed. An incremental backup copies each page whose LSN is newer than the previous incremental or full backup's LSN. There are two algorithms in use to find the set of such pages to be copied. The first one, available with all the server types and versions, is to check the page LSN directly by reading all the data pages. The second one, available with *Percona Server for MySQL*, is to enable the *changed page tracking* feature on the server, which will note the pages as they are being changed. This information will be then written out in a compact separate so-called bitmap file. The *xtrabackup* binary will use that file to read only the data pages it needs for the incremental backup, potentially saving many read requests. The latter algorithm is enabled by default if the *xtrabackup* binary finds the bitmap file. It is possible to specify **--incremental-force-scan** to read all the pages even if the bitmap data is available. Incremental backups do not actually compare the data files to the previous backup's data files. In fact, you can use **--incremental-lsn** to perform an incremental backup without even having the previous backup, if you know its LSN. Incremental backups simply read the pages and compare their LSN to the last backup's LSN. You still need a full backup to recover the incremental changes, however; without a full backup to act as a base, the incremental backups are useless. ### Creating an Incremental Backup To make an incremental backup, begin with a full backup as usual. The *xtrabackup* binary writes a file called **xtrabackup\_checkpoints** into the backup's target directory. This file contains a line showing the **to\_lsn**, which is the database's LSN at the end of the backup. Create the full backup with a command such as the following: ``` $ xtrabackup --backup --target-dir=/data/backups/base --datadir=/var/lib/mysql/ ``` If you look at the **xtrabackup\_checkpoints** file, you should see contents similar to the following: ``` backup_type = full-backuped from_lsn = 0 to_lsn = 1291135 ``` Now that you have a full backup, you can make an incremental backup based on it. Use a command such as the following: ``` $ xtrabackup --backup --target-dir=/data/backups/inc1 \ --incremental-basedir=/data/backups/base --datadir=/var/lib/mysql/ ``` The **/data/backups/inc1/** directory should now contain delta files, such as **ibdata1.delta** and **test/table1.ibd.delta**. These represent the changes since the **LSN 1291135**. If you examine the **xtrabackup\_checkpoints** file in this directory, you should see something similar to the following: ``` backup_type = incremental from_lsn = 1291135 to_lsn = 1291340 ``` The meaning should be self-evident. It's now possible to use this directory as the base for yet another incremental backup: ``` $ xtrabackup --backup --target-dir=/data/backups/inc2 \ --incremental-basedir=/data/backups/inc1 --datadir=/var/lib/mysql/ ``` ### Preparing the Incremental Backups The **--prepare** step for incremental backups is not the same as for normal backups. In normal backups, two types of operations are performed to make the database consistent: committed transactions are replayed from the log file against the data files, and uncommitted transactions are rolled back. You must skip the rollback of uncommitted transactions when preparing a backup, because transactions that were uncommitted at the time of your backup may be in progress, and it is likely that they will be committed in the next incremental backup. You should use the **--apply-log-only** option to prevent the rollback phase. **NOTE:** If you do not use the **--apply-log-only** option to prevent the rollback phase, then your incremental backups will be useless. After transactions have been rolled back, further incremental backups cannot be applied. Beginning with the full backup you created, you can prepare it, and then apply the incremental differences to it. Recall that you have the following backups: ``` /data/backups/base /data/backups/inc1 /data/backups/inc2 ``` To prepare the base backup, you need to run **--prepare** as usual, but prevent the rollback phase: ``` xtrabackup --prepare --apply-log-only --target-dir=/data/backups/base ``` The output should end with some text such as the following: ``` 101107 20:49:43 InnoDB: Shutdown completed; log sequence number 1291135 ``` The log sequence number should match the **to\_lsn** of the base backup, which you saw previously. This backup is actually safe to restore as-is now, even though the rollback phase has been skipped. If you restore it and start *MySQL*, *InnoDB* will detect that the rollback phase was not performed, and it will do that in the background, as it usually does for a crash recovery upon start. It will notify you that the database was not shut down normally. To apply the first incremental backup to the full backup, you should use the following command: ``` xtrabackup --prepare --apply-log-only --target-dir=/data/backups/base \ --incremental-dir=/data/backups/inc1 ``` This applies the delta files to the files in **/data/backups/base**, which rolls them forward in time to the time of the incremental backup. It then applies the redo log as usual to the result. The final data is in **/data/backups/base**, not in the incremental directory. You should see some output such as the following: ``` incremental backup from 1291135 is enabled. xtrabackup: cd to /data/backups/base/ xtrabackup: This target seems to be already prepared. xtrabackup: xtrabackup_logfile detected: size=2097152, start_lsn=(1291340) Applying /data/backups/inc1/ibdata1.delta ... Applying /data/backups/inc1/test/table1.ibd.delta ... .... snip 101107 20:56:30 InnoDB: Shutdown completed; log sequence number 1291340 ``` Again, the LSN should match what you saw from your earlier inspection of the first incremental backup. If you restore the files from **/data/backups/base**, you should see the state of the database as of the first incremental backup. Preparing the second incremental backup is a similar process: apply the deltas to the (modified) base backup, and you will roll its data forward in time to the point of the second incremental backup: ``` xtrabackup --prepare --target-dir=/data/backups/base \ --incremental-dir=/data/backups/inc2 ``` **NOTE:** **--apply-log-only** should be used when merging all incrementals except the last one. That's why the previous line doesn't contain the **--apply-log-only** option. Even if the **--apply-log-only** was used on the last step, backup would still be consistent but in that case server would perform the rollback phase. If you wish to avoid the notice that *InnoDB* was not shut down normally, when you applied the desired deltas to the base backup, you can run **--prepare** again without disabling the rollback phase. ### Restoring Incremental Backups After preparing the incremental backups, the base directory contains the same data as the full backup. To restoring this backup, you can use this command: **xtrabackup --copy-back --target-dir=BASE-DIR** You may have to change the ownership as detailed on restoring\_a\_backup. ### Incremental Streaming Backups Using xbstream Incremental streaming backups can be performed with the *xbstream* streaming option. Currently backups are packed in custom **xbstream** format. With this feature, you need to take a BASE backup as well. Making a base backup ``` $ xtrabackup --backup --target-dir=/data/backups ``` Taking a local backup ``` $ xtrabackup --backup --incremental-lsn=LSN-number --stream=xbstream --target-dir=./ > incremental.xbstream ``` Unpacking the backup ``` $ xbstream -x < incremental.xbstream ``` Taking a local backup and streaming it to the remote server and unpacking it ``` $ xtrabackup --backup --incremental-lsn=LSN-number --stream=xbstream --target-dir=./ $ ssh user@hostname " cat - | xbstream -x -C > /backup-dir/" ``` ### Partial Backups *xtrabackup* supports taking partial backups when the innodb\_file\_per\_table option is enabled. There are three ways to create partial backups: - 1\. matching the tables names with a regular expression - 2\. providing a list of table names in a file - 3\. providing a list of databases **WARNING:** Do not copy back the prepared backup. Restoring partial backups should be done by importing the tables, not by using the *--copy-back* option. It is not recommended to run incremental backups after running a partial backup. Although there are some scenarios where restoring can be done by copying back the files, this may lead to database inconsistencies in many cases and it is not a recommended way to do it. For the purposes of this manual page, we will assume that there is a database named **test** which contains tables named **t1** and **t2**. **WARNING:** If any of the matched or listed tables is deleted during the backup, *xtrabackup* will fail. ### Creating Partial Backups There are multiple ways of specifying which part of the whole data is backed up: - • Use the **--tables** option to list the table names - • Use the **--tables-file** option to list the tables in a file - • Use the **--databases** option to list the databases - • Use the **--databases-file** option to list the databases ### The *--tables* Option The first method involves the xtrabackup *--tables* option. The option's value is a regular expression that is matched against the fully-qualified database name and table name using the **databasename.tablename** format. To back up only tables in the **test** database, use the following command: ``` $ xtrabackup --backup --datadir=/var/lib/mysql --target-dir=/data/backups/ \ --tables="^test[.].*" ``` To back up only the **test.t1** table, use the following command: ``` $ xtrabackup --backup --datadir=/var/lib/mysql --target-dir=/data/backups/ \ --tables="^test[.]t1" ``` ### The *--tables-file* Option The **--tables-file** option specifies a file that can contain multiple table names, one table name per line in the file. Only the tables named in the file will be backed up. Names are matched exactly, case-sensitive, with no pattern or regular expression matching. The table names must be fully-qualified in **databasename.tablename** format. ``` $ echo "mydatabase.mytable" > /tmp/tables.txt $ xtrabackup --backup --tables-file=/tmp/tables.txt ``` ### The *--databases* and *--databases-file* options The \` --databases\` option accepts a space-separated list of the databases and tables to backup in the **databasename\[.tablename\]** format. In addition to this list, make sure to specify the **mysql**, **sys**, and **performance\_schema** databases. These databases are required when restoring the databases using *xtrabackup --copy-back*. **NOTE:** Tables processed during the --prepare step may also be added to the backup even if they are not explicitly listed by the parameter if they were created after the backup started. ``` $ xtrabackup --databases='mysql sys performance_schema test ...' ``` ### The --databases-file Option The *--databases-file* option specifies a file that can contain multiple databases and tables in the **databasename\[.tablename\]** format, one element name per line in the file. Names are matched exactly, case-sensitive, with no pattern or regular expression matching. **NOTE:** Tables processed during the --prepare step may also be added to the backup even if they are not explicitly listed by the parameter if they were created after the backup started. ### Preparing Partial Backups The procedure is analogous to restoring individual tables : apply the logs and use the *--export* option: ``` $ xtrabackup --prepare --export --target-dir=/path/to/partial/backup ``` When you use the *--prepare* option on a partial backup, you will see warnings about tables that don't exist. This is because these tables exist in the data dictionary inside InnoDB, but the corresponding .ibd files don't exist. They were not copied into the backup directory. These tables will be removed from the data dictionary, and when you restore the backup and start InnoDB, they will no longer exist and will not cause any errors or warnings to be printed to the log file. Could not find any file associated with the tablespace ID: 5 Use --innodb-directories to find the tablespace files. If that fails then use --innodb-force-recovery=1 to ignore this and to permanently lose all changes to the missing tablespace(s). ### Restoring Partial Backups Restoring should be done by restoring individual tables in the partial backup to the server. It can also be done by copying back the prepared backup to a "clean" datadir (in that case, make sure to include the **mysql** database) to the datadir you are moving the backup to. A system database can be created with the following: ``` $ sudo mysql --initialize --user=mysql ``` Once you start the server, you may see mysql complaining about missing tablespaces: ``` 2021-07-19T12:42:11.077200Z 1 [Warning] [MY-012351] [InnoDB] Tablespace 4, name 'test1/t1', file './d2/test1.ibd' is missing! 2021-07-19T12:42:11.077300Z 1 [Warning] [MY-012351] [InnoDB] Tablespace 4, name 'test1/t1', file './d2/test1.ibd' is missing! ``` In order to clean the orphan database from the data dictionary, you must manually create the missing database directory and then **DROP** this database from the server. Example of creating the missing database: ``` $ mkdir /var/lib/mysql/test1/d2 ``` Example of dropping the database from the server: ``` mysql> DROP DATABASE d2; Query OK, 2 rows affected (0.5 sec) ``` ## ADVANCED FEATURES ### Analyzing Table Statistics The *xtrabackup* binary can analyze InnoDB data files in read-only mode to give statistics about them. To do this, you should use the **--stats** option. You can combine this with the **--tables** option to limit the files to examine. It also uses the **--use-memory** option. You can perform the analysis on a running server, with some chance of errors due to the data being changed during analysis. Or, you can analyze a backup copy of the database. Either way, to use the statistics feature, you need a clean copy of the database including correctly sized log files, so you need to execute with **--prepare** twice to use this functionality on a backup. The result of running on a backup might look like the following: ``` table: test/table1, index: PRIMARY, space id: 12, root page 3 estimated statistics in dictionary: key vals: 25265338, leaf pages 497839, size pages 498304 real statistics: level 2 pages: pages=1, data=5395 bytes, data/pages=32% level 1 pages: pages=415, data=6471907 bytes, data/pages=95% leaf pages: recs=25958413, pages=497839, data=7492026403 bytes, data/pages=91% ``` This can be interpreted as follows: - • The first line simply shows the table and index name and its internal identifiers. If you see an index named **GEN\_CLUST\_INDEX**, that is the table's clustered index, automatically created because you did not explicitly create a **PRIMARY KEY**. - • The estimated statistics in dictionary information is similar to the data that's gathered through **ANALYZE TABLE** inside of *InnoDB* to be stored as estimated cardinality statistics and passed to the query optimizer. - • The real statistics information is the result of scanning the data pages and computing exact information about the index. - • **The level \ pages**: output means that the line shows information about pages at that level in the index tree. The larger **\** is, the farther it is from the leaf pages, which are level 0. The first line is the root page. - • The **leaf pages** output shows the leaf pages, of course. This is where the table's data is stored. - • The **external pages**: output (not shown) shows large external pages that hold values too long to fit in the row itself, such as long **BLOB** and **TEXT** values. - • The **recs** is the real number of records (rows) in leaf pages. - • The **pages** is the page count. - • The **data** is the total size of the data in the pages, in bytes. - • The **data/pages** is calculated as (**data** / (**pages** \* **PAGE\_SIZE**)) \* 100%. It will never reach 100% because of space reserved for page headers and footers. A more detailed example is posted as a MySQL Performance Blog *post*. ### Script to Format Output The following script can be used to summarize and tabulate the output of the statistics information: ``` tabulate-xtrabackup-stats.pl #!/usr/bin/env perl use strict; use warnings FATAL => 'all'; my $script_version = "0.1"; my $PG_SIZE = 16_384; # InnoDB defaults to 16k pages, change if needed. my ($cur_idx, $cur_tbl); my (%idx_stats, %tbl_stats); my ($max_tbl_len, $max_idx_len) = (0, 0); while ( my $line = <> ) { if ( my ($t, $i) = $line =~ m/table: (.*), index: (.*), space id:/ ) { $t =~ s!/!.!; $cur_tbl = $t; $cur_idx = $i; if ( length($i) > $max_idx_len ) { $max_idx_len = length($i); } if ( length($t) > $max_tbl_len ) { $max_tbl_len = length($t); } } elsif ( my ($kv, $lp, $sp) = $line =~ m/key vals: (\d+), \D*(\d+), \D*(\d+)/ ) { @{$idx_stats{$cur_tbl}->{$cur_idx}}{qw(est_kv est_lp est_sp)} = ($kv, $lp, $sp); $tbl_stats{$cur_tbl}->{est_kv} += $kv; $tbl_stats{$cur_tbl}->{est_lp} += $lp; $tbl_stats{$cur_tbl}->{est_sp} += $sp; } elsif ( my ($l, $pages, $bytes) = $line =~ m/(?:level (\d+)|leaf) pages:.*pages=(\d+), data=(\d+) bytes/ ) { $l ||= 0; $idx_stats{$cur_tbl}->{$cur_idx}->{real_pages} += $pages; $idx_stats{$cur_tbl}->{$cur_idx}->{real_bytes} += $bytes; $tbl_stats{$cur_tbl}->{real_pages} += $pages; $tbl_stats{$cur_tbl}->{real_bytes} += $bytes; } } my $hdr_fmt = "%${max_tbl_len}s %${max_idx_len}s %9s %10s %10s\n"; my @headers = qw(TABLE INDEX TOT_PAGES FREE_PAGES PCT_FULL); printf $hdr_fmt, @headers; my $row_fmt = "%${max_tbl_len}s %${max_idx_len}s %9d %10d %9.1f%%\n"; foreach my $t ( sort keys %tbl_stats ) { my $tbl = $tbl_stats{$t}; printf $row_fmt, $t, "", $tbl->{est_sp}, $tbl->{est_sp} - $tbl->{real_pages}, $tbl->{real_bytes} / ($tbl->{real_pages} * $PG_SIZE) * 100; foreach my $i ( sort keys %{$idx_stats{$t}} ) { my $idx = $idx_stats{$t}->{$i}; printf $row_fmt, $t, $i, $idx->{est_sp}, $idx->{est_sp} - $idx->{real_pages}, $idx->{real_bytes} / ($idx->{real_pages} * $PG_SIZE) * 100; } } ``` Sample Script Output The output of the above Perl script, when run against the sample shown in the previously mentioned blog post, will appear as follows: ``` TABLE INDEX TOT_PAGES FREE_PAGES PCT_FULL art.link_out104 832383 38561 86.8% art.link_out104 PRIMARY 498304 49 91.9% art.link_out104 domain_id 49600 6230 76.9% art.link_out104 domain_id_2 26495 3339 89.1% art.link_out104 from_message_id 28160 142 96.3% art.link_out104 from_site_id 38848 4874 79.4% art.link_out104 revert_domain 153984 19276 71.4% art.link_out104 site_message 36992 4651 83.4% ``` The columns are the table and index, followed by the total number of pages in that index, the number of pages not actually occupied by data, and the number of bytes of real data as a percentage of the total size of the pages of real data. The first line in the above output, in which the **INDEX** column is empty, is a summary of the entire table. ### Working with Binary Logs The **xtrabackup** binary integrates with the **log\_status table**. This integration enables **xtrabackup** to print out the backup's corresponding binary log position, so that you can use this binary log position to provision a new replica or perform point-in-time recovery. ### Finding the Binary Log Position You can find the binary log position corresponding to a backup after the backup has been taken. If your backup is from a server with binary logging enabled, **xtrabackup** creates a file named **xtrabackup\_binlog\_info** in the target directory. This file contains the binary log file name and position of the exact point when the backup was taken. The output is similar to the following during the backup stage: ``` 210715 14:14:59 Backup created in directory '/backup/' MySQL binlog position: filename 'binlog.000002', position '156' . . . 210715 14:15:00 completed OK! ``` **NOTE:** As of Percona XtraBackup 8.0.26-18.0, xtrabackup no longer creates the **xtrabackup\_binlog\_pos\_innodb** file. This change is because MySQL and Percona Server no longer update the binary log information on global transaction system section of **ibdata**. You should rely on **xtrabackup\_binlog\_info** regardless of the storage engine in use. ### Point-In-Time Recovery To perform a point-in-time recovery from an **xtrabackup** backup, you should prepare and restore the backup, and then replay binary logs from the point shown in the **xtrabackup\_binlog\_info** file. A more detailed procedure is found here. ### Setting Up a New Replication Replica To set up a new replica, you should prepare the backup, and restore it to the data directory of your new replication replica. If you are using version 8.0.22 or earlier, in your **CHANGE MASTER TO** command, use the binary log filename and position shown in the **xtrabackup\_binlog\_info** file to start replication. If you are using 8.0.23 or later, use the *CHANGE\_REPLICATION\_SOURCE\_TO and the appropriate options*. **CHANGE\_MASTER\_TO** is deprecated. A more detailed procedure is found in ../howtos/setting\_up\_replication. ### Restoring Individual Tables *Percona XtraBackup* can export a table that is contained in its own *.ibd* file. With *Percona XtraBackup*, you can export individual tables from any *InnoDB* database, and import them into *Percona Server for MySQL* with *XtraDB* or *MySQL* 8.0. The source doesn't have to be *XtraDB* or *MySQL* 8.0, but the destination does. This method only works on individual *.ibd* files. The following example exports and imports the following table: ``` CREATE TABLE export_test ( a int(11) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ``` ### Exporting the Table Created the table in *innodb\_file\_per\_table* mode, so after taking a backup as usual with the *--backup* option, the *.ibd* file exists in the target directory: ``` $ find /data/backups/mysql/ -name export_test.* /data/backups/mysql/test/export_test.ibd ``` when you prepare the backup, add the *--export* option to the command. Here is an example: ``` $ xtrabackup --prepare --export --target-dir=/data/backups/mysql/ ``` **NOTE:** If you restore an encrypted InnoDB tablespace table, add the keyring file: ``` $ xtrabackup --prepare --export --target-dir=/tmp/table \ --keyring-file-data=/var/lib/mysql-keyring/keyring ``` Now you should see an *.exp* file in the target directory: ``` $ find /data/backups/mysql/ -name export_test.* /data/backups/mysql/test/export_test.exp /data/backups/mysql/test/export_test.ibd /data/backups/mysql/test/export_test.cfg ``` These three files are the only files required to import the table into a server running *Percona Server for MySQL* with *XtraDB* or *MySQL* 8.0. In case the server uses *InnoDB* *Tablespace Encryption* adds an additional *.cfp* file which contains the transfer key and an encrypted tablespace key. **NOTE:** The *.cfg* metadata file contains an *InnoDB* dictionary dump in a special format. This format is different from the *.exp* one which is used in *XtraDB* for the same purpose. A *.cfg\`* file is not required to import a tablespace to *MySQL* 8.0 or Percona Server for MySQL 8.0. A tablespace is imported successfully even if the table is from another server, but *InnoDB* performs a schema validation if the corresponding *.cfg* file is located in the same directory. ### Importing the Table On the destination server running *Percona Server for MySQL* with *XtraDB* and *innodb\_import\_table\_from\_xtrabackup* option enabled, or *MySQL* 8.0, create a table with the same structure, and then perform the following steps: - 1\. Run the **ALTER TABLE test.export\_test DISCARD TABLESPACE;** command. If you see the following error, enable *innodb\_file\_per\_table* and create the table again. - Error ERROR 1030 (HY000): Got error -1 from storage engine - 2\. Copy the exported files to the **test/** subdirectory of the destination server's data directory - 3\. Run **ALTER TABLE test.export\_test IMPORT TABLESPACE;** The table is imported, and you can run a **SELECT** to see the imported data. ### LRU dump backup *Percona XtraBackup* includes a saved buffer pool dump into a backup to enable reducing the warm up time. It restores the buffer pool state from **ib\_buffer\_pool** file after restart. *Percona XtraBackup* discovers **ib\_buffer\_pool** and backs it up automatically. \[image\] If the buffer restore option is enabled in **my.cnf** buffer pool will be in the warm state after backup is restored. **SEE ALSO:** - ***MySQL* Documentation: Saving and Restoring the Buffer Pool State** *https://dev.mysql.com/doc/refman/8.0/en/innodb-preload-buffer-pool.html* ### Streaming Backups **Percona XtraBackup** supports streaming mode. Streaming mode sends a backup to **STDOUT** in the *xbstream* format instead of copying the files to the backup directory. This method allows you to use other programs to filter the output of the backup, providing greater flexibility for storage of the backup. For example, compression is achieved by piping the output to a compression utility. One of the benefits of streaming backups and using Unix pipes is that the backups can be automatically encrypted. To use the streaming feature, you must use the **--stream**, providing the format of the stream (**xbstream** ) and where to store the temporary files: ``` $ xtrabackup --stream=xbstream --target-dir=/tmp ``` *xtrabackup* uses *xbstream* to stream all of the data files to **STDOUT**, in a special **xbstream** format. After it finishes streaming all of the data files to **STDOUT**, it stops xtrabackup and streams the saved log file too. **SEE ALSO:** - **More information about *xbstream*** xbstream\_binary When compression is enabled, *xtrabackup* compresses the output data, except for the meta and non-InnoDB files which are not compressed, using the specified compression algorithm. The only currently supported algorithm is **quicklz**. The resulting files have the **qpress** archive format, i.e. every \*.qp file produced by xtrabackup is essentially a one-file qpress archive and can be extracted and uncompressed by the *qpress file archiver* which is available from Percona Software repositories. Using *xbstream* as a stream option, backups can be copied and compressed in parallel. This option can significantly improve the speed of the backup process. In case backups were both compressed and encrypted, they must be decrypted before they are uncompressed. | | | | --- | --- | | Task | Command | | Stream the backup into an archive named **backup.xbstream** | **xtrabackup --backup --stream=xbstream --target-dir=./ \> backup.xbstream** | | Stream the backup into a *compressed* archive named **backup.xbstream** | **xtrabackup --backup --stream=xbstream --compress --target-dir=./ \> backup.xbstream** | | Encrypt the backup | $ xtrabackup --backup --stream=xbstream ./ \> backup.xbstream gzip - \| openssl des3 -salt -k "password" \> backup.xbstream.gz.des3 | | Unpack the backup to the current directory | **xbstream -x \< backup.xbstream** | | Send the backup compressed directly to another host and unpack it | **xtrabackup --backup --compress --stream=xbstream --target-dir=./ \| ssh user@otherhost "xbstream -x"** | | Send the backup to another server using **netcat**. | On the destination host: $ nc -l 9999 \| cat - \> /data/backups/backup.xbstream On the source host: $ xtrabackup --backup --stream=xbstream ./ \| nc desthost 9999 | | Send the backup to another server using a one-liner: | $ ssh *user@desthost* "( nc -l 9999 \> /data/backups/backup.xbstream & )" && xtrabackup --backup --stream=xbstream ./ \| nc desthost 9999 | | Throttle the throughput to 10MB/sec using the **pipe viewer** tool \[1\] | $ xtrabackup --backup --stream=xbstream ./ \| pv -q -L10m ssh *user@desthost* "cat - \> /data/backups/backup.xbstream" | | Checksumming the backup during the streaming: | On the destination host: $ nc -l 9999 \| tee \>(sha1sum \> destination\_checksum) \> /data/backups/backup.xbstream On the source host: $ xtrabackup --backup --stream=xbstream ./ \| tee \>(sha1sum \> source\_checksum) \| nc desthost 9999 Compare the checksums on the source host: $ cat source\_checksum 65e4f916a49c1f216e0887ce54cf59bf3934dbad - Compare the checksums on the destination host: $ cat destination\_checksum 65e4f916a49c1f216e0887ce54cf59bf3934dbad - | | Parallel compression with parallel copying backup | **xtrabackup --backup --compress --compress-threads=8 --stream=xbstream --parallel=4 --target-dir=./ \> backup.xbstream** | ## FOOTNOTES - \[1\] Install from the *official site* or from the distribution package (**apt install pv**) Note that the streamed backup will need to be prepared before restoration. Streaming mode does not prepare the backup. ### Encrypting Backups *Percona XtraBackup* supports encrypting and decrypting local and streaming backups with *xbstream* option adding another layer of protection. The encryption is implemented using the **libgcrypt** library from GnuPG. ### Creating Encrypted Backups To make an encrypted backup the following options need to be specified (options **--encrypt-key** and **--encrypt-key-file** are mutually exclusive, i.e. just one of them needs to be provided): - • **--encrypt** - • :option:\` --encrypt-key\` - • :option:\` --encrypt-key-file\` Both the **--encrypt-key** option and **--encrypt-key-file** option can be used to specify the encryption key. An encryption key can be generated with a command like **openssl rand -base64 32** Example output of that command should look like this: ``` U2FsdGVkX19VPN7VM+lwNI0fePhjgnhgqmDBqbF3Bvs= ``` This value then can be used as the encryption key ### The --encrypt-key Option Example of the *xtrabackup* command using the **--encrypt-key** should look like this: ``` $ xtrabackup --backup --encrypt=AES256 --encrypt-key="U2FsdGVkX19VPN7VM+lwNI0fePhjgnhgqmDBqbF3Bvs=" --target-dir=/data/backup ``` ### The --encrypt-key-file Option Use the **--encrypt-key-file** option as follows: ``` $ xtrabackup --backup --encrypt=AES256 --encrypt-key-file=/data/backups/keyfile --target-dir=/data/backup ``` **NOTE:** Depending on the text editor that you use to make the **KEYFILE**, the editor can automatically insert the CRLF (end of line) character. This will cause the key size to grow and thus making it invalid. The suggested way to create the file is by using the command line: **echo -n "U2FsdGVkX19VPN7VM+lwNI0fePhjgnhgqmDBqbF3Bvs=" \> /data/backups/keyfile**. ### Optimizing the encryption process Two new options are available for encrypted backups that can be used to speed up the encryption process. These are **--encrypt-threads** and **--encrypt-chunk-size**. By using the **--encrypt-threads** option multiple threads can be specified to be used for encryption in parallel. Option **--encrypt-chunk-size** can be used to specify the size (in bytes) of the working encryption buffer for each encryption thread (default is 64K). ### Decrypting Encrypted Backups Backups can be decrypted with xbcrypt. The following one-liner can be used to encrypt the whole folder: ``` $ for i in `find . -iname "*\.xbcrypt"`; do xbcrypt -d --encrypt-key-file=/root/secret_key --encrypt-algo=AES256 < $i > $(dirname $i)/$(basename $i .xbcrypt) && rm $i; done ``` *Percona XtraBackup* **--decrypt** option has been implemented that can be used to decrypt the backups: ``` $ xtrabackup --decrypt=AES256 --encrypt-key="U2FsdGVkX19VPN7VM+lwNI0fePhjgnhgqmDBqbF3Bvs=" --target-dir=/data/backup/ ``` *Percona XtraBackup* doesn't automatically remove the encrypted files. In order to clean up the backup directory users should remove the **\*.xbcrypt** files. **NOTE:** **--parallel** can be used with **--decrypt** option to decrypt multiple files simultaneously. When the files are decrypted, the backup can be prepared. ### Preparing Encrypted Backups After the backups have been decrypted, they can be prepared in the same way as the standard full backups with the **--prepare** option: ``` $ xtrabackup --prepare --target-dir=/data/backup/ ``` ### Restoring Encrypted Backups *xtrabackup* offers the **--copy-back** option to restore a backup to the server's datadir: ``` $ xtrabackup --copy-back --target-dir=/data/backup/ ``` It will copy all the data-related files back to the server's datadir, determined by the server's **my.cnf** configuration file. You should check the last line of the output for a success message: ``` 150318 11:08:13 xtrabackup: completed OK! ``` **SEE ALSO:** - **GnuPG Documentation: libgcrypt library** *http://www.gnupg.org/documentation/manuals/gcrypt/* ### FLUSH TABLES WITH READ LOCK option The **FLUSH TABLES WITH READ LOCK** option does the following with a global read lock: - • Closes all open tables - • Locks all tables for all databases Release the lock with **UNLOCK TABLES**. **NOTE:** **FLUSH TABLES WITH READ LOCK** does not prevent inserting rows into the log tables. To ensure consistent backups, use the **FLUSH TABLES WITH READ LOCK** option before taking a non-InnoDB file backup. The option does not affect long-running queries. Long-running queries with **FLUSH TABLES WITH READ LOCK** enabled can leave the server in a read-only mode until the queries finish. Killing the **FLUSH TABLES WITH READ LOCK** does not help if the database is in either the **Waiting for table flush** or **Waiting for master to send event** state. To return to normal operation, you must kill any long-running queries. **NOTE:** All described in this section has no effect when backup locks are used. *Percona XtraBackup* will use *Backup locks* where available as a lightweight alternative to **FLUSH TABLES WITH READ** **LOCK**. This feature is available in *Percona Server for MySQL* 5.6+. *Percona XtraBackup* uses this automatically to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. In order to prevent this from happening two things have been implemented: - • *xtrabackup* waits for a good moment to issue the global lock - • *xtrabackup* kills all queries or only the SELECT queries which prevent the global lock from being acquired ### Waiting for queries to finish You should issue a global lock when no long queries are running. Waiting to issue the global lock for extended period of time is not a good method. The wait can extend the time needed for backup to take place. The *--ftwrl-wait-timeout* option can limit the waiting time. If it cannot issue the lock during this time, *xtrabackup* stops the option, exits with an error message, and backup is not be taken. The default value for this option is zero (0) value which turns off the option. Another possibility is to specify the type of query to wait on. In this case **--ftwrl-wait-query-type**. Possible values are **all** and **update**. When **all** is used *xtrabackup* will wait for all long running queries (execution time longer than allowed by **--ftwrl-wait-threshold**) to finish before running the **FLUSH TABLES WITH READ LOCK**. When **update** is used *xtrabackup* will wait on **UPDATE/ALTER/REPLACE/INSERT** queries to finish. The time needed for a specific query to complete is hard to predict. We assume that the long-running queries will not finish in a timely manner. Other queries which run for a short time finish quickly. *xtrabackup* uses the value of *--ftwrl-wait-threshold* option to specify the long-running queries and will block a global lock. In order to use this option xtrabackup user should have **PROCESS** and **SUPER** privileges. ### Killing the blocking queries The second option is to kill all the queries which prevent from acquiring the global lock. In this case, all queries which run longer than **FLUSH TABLES WITH** **READ LOCK** are potential blockers. Although all queries can be killed, additional time can be specified for the short running queries to finish using the **--kill-long-queries-timeout** option. This option specifies the time for queries to complete, after the value is reached, all the running queries will be killed. The default value is zero, which turns this feature off. The **--kill-long-query-type** option can be used to specify all or only **SELECT** queries that are preventing global lock from being acquired. In order to use this option xtrabackup user should have **PROCESS** and **SUPER** privileges. ### Options summary - • **--ftwrl-wait-timeout** (seconds) - how long to wait for a good moment. Default is 0, not to wait. - • **--ftwrl-wait-query-type** - which long queries should be finished before **FLUSH TABLES WITH READ LOCK** is run. Default is all. - • **--ftwrl-wait-threshold** (seconds) - how long query should be running before we consider it long running and potential blocker of global lock. - • **--kill-long-queries-timeout** (seconds) - how many time we give for queries to complete after **FLUSH TABLES WITH READ LOCK** is issued before start to kill. Default if **0**, not to kill. - • **--kill-long-query-type** - which queries should be killed once **kill-long-queries-timeout** has expired. ### Example Running the *xtrabackup* with the following options will cause *xtrabackup* to spend no longer than 3 minutes waiting for all queries older than 40 seconds to complete. ``` $ xtrabackup --backup --ftwrl-wait-threshold=40 \ --ftwrl-wait-query-type=all --ftwrl-wait-timeout=180 \ --kill-long-queries-timeout=20 --kill-long-query-type=all \ --target-dir=/data/backups/ ``` After **FLUSH TABLES WITH READ LOCK** is issued, *xtrabackup* will wait for 20 seconds for lock to be acquired. If lock is still not acquired after 20 seconds, it will kill all queries which are running longer that the **FLUSH TABLES WITH** **READ LOCK**. ### Accelerating the backup process Copying with the **--parallel** and *--compress-threads* Options When making a local or streaming backup with *xbstream* option, multiple files can be copied at the same time when using the **--parallel** option. This option specifies the number of threads created by *xtrabackup* to copy data files. To take advantage of this option either the multiple tablespaces option must be enabled (innodb\_file\_per\_table) or the shared tablespace must be stored in multiple ibdata files with the innodb\_data\_file\_path option. Having multiple files for the database (or splitting one into many) doesn't have a measurable impact on performance. As this feature is implemented **at the file level**, concurrent file transfer can sometimes increase I/O throughput when doing a backup on highly fragmented data files, due to the overlap of a greater number of random read requests. You should consider tuning the filesystem also to obtain the maximum performance (e.g. checking fragmentation). If the data is stored on a single file, this option will have no effect. To use this feature, simply add the option to a local backup, for example: ``` $ xtrabackup --backup --parallel=4 --target-dir=/path/to/backup ``` By using the *xbstream* in streaming backups, you can additionally speed up the compression process with the **--compress-threads** option. This option specifies the number of threads created by *xtrabackup* for for parallel data compression. The default value for this option is 1. To use this feature, simply add the option to a local backup, for example: ``` $ xtrabackup --backup --stream=xbstream --compress --compress-threads=4 --target-dir=./ > backup.xbstream ``` Before applying logs, compressed files will need to be uncompressed. The **--rsync** Option In order to speed up the backup process and to minimize the time **FLUSH TABLES** **WITH READ LOCK** is blocking the writes, the option **--rsync** should be used. When this option is specified, *xtrabackup* uses **rsync** to copy all non-InnoDB files instead of spawning a separate **cp** for each file, which can be much faster for servers with a large number of databases or tables. *xtrabackup* will call the **rsync** twice, once before the **FLUSH** **TABLES WITH READ LOCK** and once during to minimize the time the read lock is being held. During the second **rsync** call, it will only synchronize the changes to non-transactional data (if any) since the first call performed before the **FLUSH TABLES WITH READ LOCK**. Note that *Percona XtraBackup* will use *Backup locks* where available as a lightweight alternative to **FLUSH TABLES WITH READ** **LOCK**. This feature is available in *Percona Server for MySQL* 5.6+. *Percona XtraBackup* uses this automatically to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. **NOTE:** This option cannot be used together with the **--stream** option. ### Point-In-Time recovery Recovering up to particular moment in database's history can be done with *xtrabackup* and the binary logs of the server. Note that the binary log contains the operations that modified the database from a point in the past. You need a full datadir as a base, and then you can apply a series of operations from the binary log to make the data match what it was at the point in time you want. ``` $ xtrabackup --backup --target-dir=/path/to/backup $ xtrabackup --prepare --target-dir=/path/to/backup ``` For more details on these procedures, see creating\_a\_backup and preparing\_a\_backup. Now, suppose that some time has passed, and you want to restore the database to a certain point in the past, having in mind that there is the constraint of the point where the snapshot was taken. To find out what is the situation of binary logging in the server, execute the following queries: ``` mysql> SHOW BINARY LOGS; +------------------+-----------+ | Log_name | File_size | +------------------+-----------+ | mysql-bin.000001 | 126 | | mysql-bin.000002 | 1306 | | mysql-bin.000003 | 126 | | mysql-bin.000004 | 497 | +------------------+-----------+ ``` and ``` mysql> SHOW MASTER STATUS; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000004 | 497 | | | +------------------+----------+--------------+------------------+ ``` The first query will tell you which files contain the binary log and the second one which file is currently being used to record changes, and the current position within it. Those files are stored usually in the datadir (unless other location is specified when the server is started with the **--log-bin=** option). To find out the position of the snapshot taken, see the **xtrabackup\_binlog\_info** at the backup's directory: ``` $ cat /path/to/backup/xtrabackup_binlog_info mysql-bin.000003 57 ``` This will tell you which file was used at moment of the backup for the binary log and its position. That position will be the effective one when you restore the backup: ``` $ xtrabackup --copy-back --target-dir=/path/to/backup ``` As the restoration will not affect the binary log files (you may need to adjust file permissions, see restoring\_a\_backup), the next step is extracting the queries from the binary log with **mysqlbinlog** starting from the position of the snapshot and redirecting it to a file ``` $ mysqlbinlog /path/to/datadir/mysql-bin.000003 /path/to/datadir/mysql-bin.000004 \ --start-position=57 > mybinlog.sql ``` Note that if you have multiple files for the binary log, as in the example, you have to extract the queries with one process, as shown above. Inspect the file with the queries to determine which position or date corresponds to the point-in-time wanted. Once determined, pipe it to the server. Assuming the point is **11-12-25 01:00:00**: ``` $ mysqlbinlog /path/to/datadir/mysql-bin.000003 /path/to/datadir/mysql-bin.000004 \ --start-position=57 --stop-datetime="11-12-25 01:00:00" | mysql -u root -p ``` and the database will be rolled forward up to that Point-In-Time. ### Making Backups in Replication Environments There are options specific to back up from a replication replica. ### The --slave-info Option This option is useful when backing up a replication replica server. It prints the binary log position and name of the source server. It also writes this information to the **xtrabackup\_slave\_info** file as a **CHANGE MASTER** statement. This option is useful for setting up a new replica for this source. You can start a replica server with this backup and issue the statement saved in the **xtrabackup\_slave\_info** file. More details of this procedure can be found in replication\_howto. ### The --safe-slave-backup Option In order to assure a consistent replication state, this option stops the replication SQL thread and waits to start backing up until **Slave\_open\_temp\_tables** in **SHOW STATUS** is zero. If there are no open temporary tables, the backup will take place, otherwise the SQL thread will be started and stopped until there are no open temporary tables. The backup will fail if **Slave\_open\_temp\_tables** does not become zero after **--safe-slave-backup-timeout** seconds (defaults to 300 seconds). The replication SQL thread will be restarted when the backup finishes. Using this option is always recommended when taking backups from a replica server. **WARNING:** Make sure your replica is a true replica of the source before using it as a source for backup. A good tool to validate a replica is *pt-table-checksum*. ### Store backup history on the server *Percona XtraBackup* supports storing the backups history on the server. This feature was implemented in *Percona XtraBackup* 2.2. Storing backup history on the server was implemented to provide users with additional information about backups that are being taken. Backup history information will be stored in the *PERCONA\_SCHEMA.XTRABACKUP\_HISTORY* table. To use this feature the following options are available: - • **--history** =\ : This option enables the history feature and allows the user to specify a backup series name that will be placed within the history record. - • **--incremental-history-name** =\ : This option allows an incremental backup to be made based on a specific history series by name. *xtrabackup* will search the history table looking for the most recent (highest **to\_lsn**) backup in the series and take the **to\_lsn** value to use as it's starting lsn. This is mutually exclusive with **--incremental-history-uuid**, **--incremental-basedir** and **--incremental-lsn** options. If no valid LSN can be found (no series by that name) *xtrabackup* will return with an error. - • **--incremental-history-uuid** =\ : Allows an incremental backup to be made based on a specific history record identified by UUID. *xtrabackup* will search the history table looking for the record matching UUID and take the **to\_lsn** value to use as it's starting LSN. This options is mutually exclusive with **--incremental-basedir**, **--incremental-lsn** and **--incremental-history-name** options. If no valid LSN can be found (no record by that UUID or missing **to\_lsn**), *xtrabackup* will return with an error. **NOTE:** Backup that's currently being performed will **NOT** exist in the xtrabackup\_history table within the resulting backup set as the record will not be added to that table until after the backup has been taken. If you want access to backup history outside of your backup set in the case of some catastrophic event, you will need to either perform a **mysqldump**, partial backup or **SELECT** \* on the history table after *xtrabackup* completes and store the results with you backup set. For the necessary privileges, see pxb.privilege. PERCONA\_SCHEMA.XTRABACKUP\_HISTORY table This table contains the information about the previous server backups. Information about the backups will only be written if the backup was taken with **--history** option. | | | | --- | --- | | Column Name | Description | | uuid | Unique backup id | | name | User provided name of backup series. There may be multiple entries with the same name used to identify related backups in a series. | | tool\_name | Name of tool used to take backup | | tool\_command | Exact command line given to the tool with --password and --encryption\_key obfuscated | | tool\_version | Version of tool used to take backup | | ibbackup\_version | Version of the xtrabackup binary used to take backup | | server\_version | Server version on which backup was taken | | start\_time | Time at the start of the backup | | end\_time | Time at the end of the backup | | lock\_time | Amount of time, in seconds, spent calling and holding locks for **FLUSH TABLES WITH READ LOCK** | | binlog\_pos | Binlog file and position at end of **FLUSH TABLES WITH READ LOCK** | | innodb\_from\_lsn | LSN at beginning of backup which can be used to determine prior backups | | innodb\_to\_lsn | LSN at end of backup which can be used as the starting lsn for the next incremental | | partial | Is this a partial backup, if **N** that means that it's the full backup | | incremental | Is this an incremental backup | | format | Description of result format (**xbstream**) | | compact | Is this a compact backup | | compressed | Is this a compressed backup | | encrypted | Is this an encrypted backup | Limitations - • **--history** option must be specified only on the command line and not within a configuration file in order to be effective. - • **--incremental-history-name** and **--incremental-history-uuid** options must be specified only on the command line and not within a configuration file in order to be effective. ## IMPLEMENTATION ### Implementation Details This page contains notes on various internal aspects of the *xtrabackup* tool's operation. ### File Permissions *xtrabackup* opens the source data files in read-write mode, although it does not modify the files. This means that you must run *xtrabackup* as a user who has permission to write the data files. The reason for opening the files in read-write mode is that *xtrabackup* uses the embedded *InnoDB* libraries to open and read the files, and *InnoDB* opens them in read-write mode because it normally assumes it is going to write to them. ### Tuning the OS Buffers Because *xtrabackup* reads large amounts of data from the filesystem, it uses **posix\_fadvise()** where possible, to instruct the operating system not to try to cache the blocks it reads from disk. Without this hint, the operating system would prefer to cache the blocks, assuming that **xtrabackup** is likely to need them again, which is not the case. Caching such large files can place pressure on the operating system's virtual memory and cause other processes, such as the database server, to be swapped out. The **xtrabackup** tool avoids this with the following hint on both the source and destination files: ``` posix_fadvise(file, 0, 0, POSIX_FADV_DONTNEED) ``` In addition, xtrabackup asks the operating system to perform more aggressive read-ahead optimizations on the source files: ``` posix_fadvise(file, 0, 0, POSIX_FADV_SEQUENTIAL) ``` ### Copying Data Files When copying the data files to the target directory, *xtrabackup* reads and writes 1 MB of data at a time. This is not configurable. When copying the log file, *xtrabackup* reads and writes 512 bytes at a time. This is also not possible to configure, and matches InnoDB's behavior (workaround exists in *Percona Server for MySQL* because it has an option to tune **innodb\_log\_block\_size** for *XtraDB*, and in that case *Percona XtraBackup* will match the tuning). After reading from the files, **xtrabackup** iterates over the 1MB buffer a page at a time, and checks for page corruption on each page with InnoDB's **buf\_page\_is\_corrupted()** function. If the page is corrupt, it re-reads and retries up to 10 times for each page. It skips this check on the doublewrite buffer. ### *xtrabackup* Exit Codes The *xtrabackup* binary exits with the traditional success value of 0 after a backup when no error occurs. If an error occurs during the backup, the exit value is 1. In certain cases, the exit value can be something other than 0 or 1, due to the command-line option code included from the *MySQL* libraries. An unknown command-line option, for example, will cause an exit code of 255. ## REFERENCES ### The xtrabackup Option Reference This page documents all of the command-line options for the **xtrabackup** binary. ### Modes of operation You invoke *xtrabackup* in one of the following modes: - • *--backup* mode to make a backup in a target directory - • *--prepare* mode to restore data from a backup (created in *--backup* mode) - • *--copy-back* to copy data from a backup to the location that contained the original data; to move data instead of copying use the alternate *--move-back* mode. - • *--stats* mode to scan the specified data files and print out index statistics. When you intend to run *xtrabackup* in any of these modes, use the following syntax: ``` $ xtrabackup [--defaults-file=#] --backup|--prepare|--copy-back|--stats [OPTIONS] ``` For example, the *--prepare* mode is applied as follows: ``` $ xtrabackup --prepare --target-dir=/data/backup/mysql/ ``` For all modes, the default options are read from the **xtrabackup** and **mysqld** configuration groups from the following files in the given order: - 1\. **/etc/my.cnf** - 2\. **/etc/mysql/my.cnf** - 3\. **/usr/etc/my.cnf** - 4\. **~/.my.cnf**. As the first parameter to *xtrabackup* (in place of the *--defaults-file*, you may supply one of the following: - • *--print-defaults* to have *xtrabackup* print the argument list and exit. - • *--no-defaults* to forbid reading options from any file but the login file. - • *--defaults-file* to read the default options from the given file. - • *--defaults-extra-file* to read the specified additional file after the global files have been read. - • *--defaults-group-suffix* to read the configuration groups with the given suffix. The effective group name is constructed by concatenating the default configuration groups (**xtrabackup** and **mysqld**) with the given suffix. - • *--login-path* to read the given path from the login file. InnoDB Options There is a large group of InnoDB options that are normally read from the **my.cnf** configuration file, so that *xtrabackup* boots up its embedded InnoDB in the same configuration as your current server. You normally do not need to specify them explicitly. These options have the same behavior in InnoDB and XtraDB. See *--innodb-miscellaneous* for more information. ### Options - **--apply-log-only** This option causes only the redo stage to be performed when preparing a backup. It is very important for incremental backups. - **--backup** Make a backup and place it in *--target-dir*. See Creating a backup. - **--backup-lock-timeout** The timeout in seconds for attempts to acquire metadata locks. - **--backup-lock-retry-count** The number of attempts to acquire metadata locks. - **--backup-locks** This option controls if backup locks should be used instead of **FLUSH TABLES** **WITH READ LOCK** on the backup stage. The option has no effect when backup locks are not supported by the server. This option is enabled by default, disable with *--no-backup-locks*. - **--check-privileges** This option checks if *Percona XtraBackup* has all required privileges. If a missing privilege is required for the current operation, it will terminate and print out an error message. If a missing privilege is not required for the current operation, but may be necessary for some other XtraBackup operation, the process is not aborted and a warning is printed. ``` xtrabackup: Error: missing required privilege LOCK TABLES on *.* xtrabackup: Warning: missing required privilege REPLICATION CLIENT on *.* ``` - **--close-files** Do not keep files opened. When *xtrabackup* opens tablespace it normally doesn't close its file handle in order to handle the DDL operations correctly. However, if the number of tablespaces is really huge and can not fit into any limit, there is an option to close file handles once they are no longer accessed. *Percona XtraBackup* can produce inconsistent backups with this option enabled. Use at your own risk. - **--compress** This option tells *xtrabackup* to compress all output data, including the transaction log file and meta data files, using either the **quicklz** or **lz4** compression algorithm. **quicklz** is chosen by default. When using **--compress=quicklz** or **--compress**, the resulting files have the qpress archive format, i.e. every **\*.qp** file produced by *xtrabackup* is essentially a one-file qpress archive and can be extracted and uncompressed by the *qpress* file archiver. **--compress=lz4** produces **\*.lz4** files. You can extract the contents of these files by using a program such as **lz4**. **SEE ALSO:** - **QuickLZ** *http://www.quicklz.com* - **LZ4** *https://lz4.github.io/lz4/* - **--compress-chunk-size=#** Size of working buffer(s) for compression threads in bytes. The default value is 64K. - **--compress-threads=#** This option specifies the number of worker threads used by *xtrabackup* for parallel data compression. This option defaults to **1**. Parallel compression (*--compress-threads*) can be used together with parallel file copying (*--parallel*). For example, **--parallel=4 --compress --compress-threads=2** will create 4 I/O threads that will read the data and pipe it to 2 compression threads. - **--copy-back** Copy all the files in a previously made backup from the backup directory to their original locations. This option will not copy over existing files unless *--force-non-empty-directories* option is specified. - **--core-file** Write core on fatal signals. - **--databases=#** This option specifies a list of databases and tables that should be backed up. The option accepts the list of the form **"databasename1\[.table\_name1\]** **databasename2\[.table\_name2\] . . ."**. - **--databases-exclude=name** Excluding databases based on name, Operates the same way as *--databases*, but matched names are excluded from backup. Note that this option has a higher priority than *--databases*. - **--databases-file=#** This option specifies the path to the file containing the list of databases and tables that should be backed up. The file can contain the list elements of the form **databasename1\[.table\_name1\]**, one element per line. - **--datadir=DIRECTORY** The source directory for the backup. This should be the same as the datadir for your *MySQL* server, so it should be read from **my.cnf** if that exists; otherwise you must specify it on the command line. When combined with the *--copy-back* or *--move-back* option, *--datadir* refers to the destination directory. Once connected to the server, in order to perform a backup you will need **READ** and **EXECUTE** permissions at a filesystem level in the server's datadir. - **--debug-sleep-before-unlock=#** This is a debug-only option used by the *xtrabackup* test suite. - **--debug-sync=name** The debug sync point. This option is only used by the *xtrabackup* test suite. - **--decompress** Decompresses all files with the **.qp** extension in a backup previously made with the *--compress* option. The *--parallel* option will allow multiple files to be decrypted simultaneously. In order to decompress, the qpress utility MUST be installed and accessible within the path. *Percona XtraBackup* does not automatically remove the compressed files. In order to clean up the backup directory users should use *--remove-original* option. The *--decompress* option may be used with *xbstream* to decompress individual qpress files. If you used the **lz4** compression algorithm to compress the files (**--compress=lz4**), change the *--decompress* parameter accordingly: **--decompress=lz4**. - **--decompress-threads=#** Force *xbstream* to use the specified number of threads for decompressing. - **--decrypt=ENCRYPTION-ALGORITHM** Decrypts all files with the **.xbcrypt** extension in a backup previously made with *--encrypt* option. The *--parallel* option will allow multiple files to be decrypted simultaneously. *Percona XtraBackup* doesn't automatically remove the encrypted files. In order to clean up the backup directory users should use *--remove-original* option. - **--defaults-extra-file=\[MY.CNF\]** Read this file after the global files are read. Must be given as the first option on the command-line. - **--defaults-file=\[MY.CNF\]** Only read default options from the given file. Must be given as the first option on the command-line. Must be a real file; it cannot be a symbolic link. - **--defaults-group=GROUP-NAME** This option is to set the group which should be read from the configuration file. This is used by *xtrabackup* if you use the *--defaults-group* option. It is needed for **mysqld\_multi** deployments. - **--defaults-group-suffix=#** Also reads groups with concat(group, suffix). - **--dump-innodb-buffer-pool** This option controls whether or not a new dump of buffer pool content should be done. With **--dump-innodb-buffer-pool**, *xtrabackup* makes a request to the server to start the buffer pool dump (it takes some time to complete and is done in background) at the beginning of a backup provided the status variable **innodb\_buffer\_pool\_dump\_status** reports that the dump has been completed. ``` $ xtrabackup --backup --dump-innodb-buffer-pool --target-dir=/home/user/backup ``` By default, this option is set to *OFF*. If **innodb\_buffer\_pool\_dump\_status** reports that there is running dump of buffer pool, *xtrabackup* waits for the dump to complete using the value of *--dump-innodb-buffer-pool-timeout* The file **ib\_buffer\_pool** stores tablespace ID and page ID data used to warm up the buffer pool sooner. **SEE ALSO:** - ***MySQL* Documentation: Saving and Restoring the Buffer Pool State** *https://dev.mysql.com/doc/refman/5.7/en/innodb-preload-buffer-pool.html* - **--dump-innodb-buffer-pool-timeout** This option contains the number of seconds that *xtrabackup* should monitor the value of **innodb\_buffer\_pool\_dump\_status** to determine if buffer pool dump has completed. This option is used in combination with *--dump-innodb-buffer-pool*. By default, it is set to *10* seconds. - **--dump-innodb-buffer-pool-pct** This option contains the percentage of the most recently used buffer pool pages to dump. This option is effective if *--dump-innodb-buffer-pool* option is set to *ON*. If this option contains a value, *xtrabackup* sets the *MySQL* system variable **innodb\_buffer\_pool\_dump\_pct**. As soon as the buffer pool dump completes or it is stopped (see *--dump-innodb-buffer-pool-timeout*), the value of the *MySQL* system variable is restored. **SEE ALSO:** - **Changing the timeout for buffer pool dump** *--dump-innodb-buffer-pool-timeout* - ***MySQL* Documentation: innodb\_buffer\_pool\_dump\_pct system variable** *https://dev.mysql.com/doc/refman/8.0/en/innodb-parameters.html#sysvar\_innodb\_buffer\_pool\_dump\_pct* - **--encrypt=ENCRYPTION\_ALGORITHM** This option instructs xtrabackup to encrypt backup copies of InnoDB data files using the algorithm specified in the ENCRYPTION\_ALGORITHM. Currently supported algorithms are: **AES128**, **AES192** and **AES256** - **--encrypt-key=ENCRYPTION\_KEY** A proper length encryption key to use. It is not recommended to use this option where there is uncontrolled access to the machine as the command line and thus the key can be viewed as part of the process info. - **--encrypt-key-file=ENCRYPTION\_KEY\_FILE** The name of a file where the raw key of the appropriate length can be read from. The file must be a simple binary (or text) file that contains exactly the key to be used. It is passed directly to the xtrabackup child process. See the **xtrabackup** documentation for more details. - **--encrypt-threads=#** This option specifies the number of worker threads that will be used for parallel encryption/decryption. See the **xtrabackup** documentation for more details. - **--encrypt-chunk-size=#** This option specifies the size of the internal working buffer for each encryption thread, measured in bytes. It is passed directly to the xtrabackup child process. See the **xtrabackup** documentation for more details. - **--export** Create files necessary for exporting tables. See Restoring Individual Tables. - **--extra-lsndir=DIRECTORY** (for --backup): save an extra copy of the **xtrabackup\_checkpoints** and **xtrabackup\_info** files in this directory. - **--force-non-empty-directories** When specified, it makes *--copy-back* and *--move-back* option transfer files to non-empty directories. No existing files will be overwritten. If files that need to be copied/moved from the backup directory already exist in the destination directory, it will still fail with an error. - **--ftwrl-wait-timeout=SECONDS** This option specifies time in seconds that xtrabackup should wait for queries that would block **FLUSH TABLES WITH READ LOCK** before running it. If there are still such queries when the timeout expires, xtrabackup terminates with an error. Default is **0**, in which case it does not wait for queries to complete and starts **FLUSH TABLES WITH READ LOCK** immediately. Where supported *xtrabackup* will automatically use *Backup Locks* as a lightweight alternative to **FLUSH TABLES WITH READ LOCK** to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. - **--ftwrl-wait-threshold=SECONDS** This option specifies the query run time threshold which is used by xtrabackup to detect long-running queries with a non-zero value of *--ftwrl-wait-timeout*. **FLUSH TABLES WITH READ LOCK** is not started until such long-running queries exist. This option has no effect if *--ftwrl-wait-timeout* is **0**. Default value is **60** seconds. Where supported xtrabackup will automatically use *Backup Locks* as a lightweight alternative to **FLUSH TABLES WITH READ LOCK** to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. - **--ftwrl-wait-query-type=all\|update** This option specifies which types of queries are allowed to complete before xtrabackup will issue the global lock. Default is **all**. - **--galera-info** This option creates the **xtrabackup\_galera\_info** file which contains the local node state at the time of the backup. Option should be used when performing the backup of *Percona XtraDB Cluster*. It has no effect when backup locks are used to create the backup. - **--generate-new-master-key** Generate a new master key when doing a copy-back. - **--generate-transition-key** *xtrabackup* needs to access the same keyring file or vault server during *prepare* and *copy-back* but it should not depend on whether the server keys have been purged. *--generate-transition-key* creates and adds to the keyring a transition key for *xtrabackup* to use if the master key used for encryption is not found because it has been rotated and purged. - **--get-server-public-key** Get the server public key **SEE ALSO:** *MySQL* Documentation: The --get-server-public-key Option *https://dev.mysql.com/doc/refman/5.7/en/connection-options.html#option\_general\_get-server-public-key* - **--help** When run with this option or without any options *xtrabackup* displays information about how to run the program on the command line along with all supported options and variables with default values where appropriate. - **--history=NAME** This option enables the tracking of backup history in the **PERCONA\_SCHEMA.xtrabackup\_history** table. An optional history series name may be specified that will be placed with the history record for the current backup being taken. - **--host=HOST** This option accepts a string argument that specifies the host to use when connecting to the database server with TCP/IP. It is passed to the mysql child process without alteration. See **mysql --help** for details. - **--incremental** This option tells *xtrabackup* to create an incremental backup. It is passed to the *xtrabackup* child process. When this option is specified, either *--incremental-lsn* or *--incremental-basedir* can also be given. If neither option is given, option *--incremental-basedir* is passed to **xtrabackup** by default, set to the first timestamped backup directory in the backup base directory. **SEE ALSO:** - **More information about incremental backups** See section xb\_incremental - **--incremental-basedir=DIRECTORY** When creating an incremental backup, this is the directory containing the full backup that is the base dataset for the incremental backups. - **--incremental-dir=DIRECTORY** When preparing an incremental backup, this is the directory where the incremental backup is combined with the full backup to make a new full backup. - **--incremental-force-scan** When creating an incremental backup, force a full scan of the data pages in the instance being backuped even if the complete changed page bitmap data is available. - **--incremental-history-name=name** This option specifies the name of the backup series stored in the **PERCONA\_SCHEMA.xtrabackup\_history** history record to base an incremental backup on. *xtrabackup* will search the history table looking for the most recent (highest **innodb\_to\_lsn**), successful backup in the series and take the to\_lsn value to use as the starting **lsn** for the incremental backup. This will be mutually exclusive with *--incremental-history-uuid*, *--incremental-basedir* and *--incremental-lsn*. If no valid lsn can be found (no series by that name, no successful backups by that name) *xtrabackup* will return with an error. It is used with the *--incremental* option. - **--incremental-history-uuid=name** This option specifies the *UUID* of the specific history record stored in the **PERCONA\_SCHEMA.xtrabackup\_history** to base an incremental backup on. *--incremental-history-name*, *--incremental-basedir* and *--incremental-lsn*. If no valid lsn can be found (no success record with that *UUID*) *xtrabackup* will return with an error. It is used with the --incremental option. - **--incremental-lsn=LSN** When creating an incremental backup, you can specify the log sequence number (LSN) instead of specifying *--incremental-basedir*. For databases created in 5.1 and later, specify the LSN as a single 64-bit integer. **ATTENTION**: If a wrong LSN value is specified (a user error which *Percona XtraBackup* is unable to detect), the backup will be unusable. Be careful! - **--innodb\[=name\]** This option is ignored for MySQL option compatibility. - **--innodb-miscellaneous** There is a large group of InnoDB options that are normally read from the **my.cnf** configuration file, so that *xtrabackup* boots up its embedded InnoDB in the same configuration as your current server. You normally do not need to specify these explicitly. These options have the same behavior in InnoDB and XtraDB: - • \--innodb-adaptive-hash-index - • \--innodb-additional-mem-pool-size - • \--innodb-autoextend-increment - • \--innodb-buffer-pool-size - • \--innodb-buffer-pool-filename - • \--innodb-checksum-algorithm - • \--innodb-checksums - • \--innodb-data-file-path - • \--innodb-data-home-dir - • \--innodb-directories - • \--innodb-doublewrite-file - • \--innodb-doublewrite - • \--innodb-extra-undoslots - • \--innodb-fast-checksum - • \--innodb-file-io-threads - • \--innodb-file-per-table - • \--innodb-flush-log-at-trx-commit - • \--innodb-flush-method - • \--innodb-io-capacity - • \--innodb-lock-wait-timeout - • \--innodb-log-block-size - • \--innodb-log-buffer-size - • \--innodb-log-checksums - • \--innodb-log-files-in-group - • \--innodb-log-file-size - • \--innodb-log-group-home-dir - • \--innodb-max-dirty-pages-pct - • \--innodb-open-files - • \--innodb-page-size - • \--innodb-read-io-threads - • \--innodb-redo-log-encrypt - • \--innodb-undo-directory - • \--innodb-undo-log-encrypt - • \--innodb-undo-tablespaces\` - • \--innodb-use-native-aio - • \--innodb-write-io-threads - **--keyring-file-data=FILENAME** The path to the keyring file. Combine this option with *--xtrabackup-plugin-dir*. - **--kill-long-queries-timeout=SECONDS** This option specifies the number of seconds *xtrabackup* waits between starting **FLUSH TABLES WITH READ LOCK** and killing those queries that block it. Default is 0 seconds, which means *xtrabackup* will not attempt to kill any queries. In order to use this option xtrabackup user should have the **PROCESS** and **SUPER** privileges. Where supported, *xtrabackup* automatically uses *Backup Locks* as a lightweight alternative to **FLUSH TABLES WITH READ LOCK** to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. - **--kill-long-query-type=all\|select** This option specifies which types of queries should be killed to unblock the global lock. Default is "select". - **--lock-ddl** Issue **LOCK TABLES FOR BACKUP** if it is supported by server (otherwise use **LOCK INSTANCE FOR BACKUP**) at the beginning of the backup to block all DDL operations. **NOTE:** Prior to *Percona XtraBackup* 8.0.22-15.0, using a *safe-slave-backup* stops the SQL replica thread after the InnoDB tables and before the non-InnoDB tables are backed up. As of *Percona XtraBackup* 8.0.22-15.0, using a *safe-slave-backup* option stops the SQL replica thread before copying the InnoDB files. - **--lock-ddl-per-table** Lock DDL for each table before xtrabackup starts to copy it and until the backup is completed. **NOTE:** As of *Percona XtraBackup* 8.0.15, the *--lock-ddl-per-table* option is deprecated. Use the *--lock-ddl* option instead. - **--lock-ddl-timeout** If **LOCK TABLES FOR BACKUP** or **LOCK INSTANCE FOR BACKUP** does not return within given timeout, abort the backup. - **--log** This option is ignored for *MySQL* - **--log-bin** The base name for the log sequence. - **--log-bin-index=name** File that holds the names for binary log files. - **--log-copy-interval=#** This option specifies the time interval between checks done by the log copying thread in milliseconds (default is 1 second). - **--login-path** Read the given path from the login file. - **--move-back** Move all the files in a previously made backup from the backup directory to their original locations. As this option removes backup files, it must be used with caution. - **--no-backup-locks** Explicity disables the *--backup-locks* option which is enabled by default. - **--no-defaults** The default options are only read from the login file. - **--no-lock** Use this option to disable table lock with **FLUSH TABLES WITH READ** **LOCK**. Use it only if ALL your tables are InnoDB and you **DO NOT CARE** about the binary log position of the backup. This option shouldn't be used if there are any **DDL** statements being executed or if any updates are happening on non-InnoDB tables (this includes the system MyISAM tables in the *mysql* database), otherwise it could lead to an inconsistent backup. Where supported *xtrabackup* will automatically use *Backup Locks* as a lightweight alternative to **FLUSH TABLES WITH READ LOCK** to copy non-InnoDB data to avoid blocking DML queries that modify InnoDB tables. If you are considering to use this because your backups are failing to acquire the lock, this could be because of incoming replication events are preventing the lock from succeeding. Please try using *--safe-slave-backup* to momentarily stop the replication replica thread, this may help the backup to succeed and you do not need to use this option. - **--no-server-version-check** Implemented in *Percona XtraBackup* 8.0.21. The **--no-server-version-check** option disables the server version check. The default behavior runs a check that compares the source system version to the *Percona XtraBackup* version. If the source system version is higher than the XtraBackup version, the backup is aborted with a message. Adding the option overrides this check, and the backup proceeds, but there may be issues with the backup. See comparison for more information. - **--no-version-check** This option disables the version check. If you do not pass this option, the automatic version check is enabled implicitly when *xtrabackup* runs in the **--backup** mode. To disable the version check, you should pass explicitly the **--no-version-check** option when invoking *xtrabackup*. When the automatic version check is enabled, *xtrabackup* performs a version check against the server on the backup stage after creating a server connection. *xtrabackup* sends the following information to the server: - • MySQL flavour and version - • Operating system name - • Percona Toolkit version - • Perl version Each piece of information has a unique identifier. This is a MD5 hash value that Percona Toolkit uses to obtain statistics about how it is used. This is a random UUID; no client information is either collected or stored. - **--open-files-limit=#** The maximum number of file descriptors to reserve with setrlimit(). - **--parallel=#** This option specifies the number of threads to use to copy multiple data files concurrently when creating a backup. The default value is 1 (i.e., no concurrent transfer). In *Percona XtraBackup* 2.3.10 and newer, this option can be used with the *--copy-back* option to copy the user data files in parallel (redo logs and system tablespaces are copied in the main thread). - **--password=PASSWORD** This option specifies the password to use when connecting to the database. It accepts a string argument. See **mysql --help** for details. - **--plugin-load** List of plugins to load. - **--port=PORT** This option accepts a string argument that specifies the port to use when connecting to the database server with TCP/IP. It is passed to the **mysql** child process without alteration. See **mysql** **--help** for details. - **--prepare** Makes **xtrabackup** perform a recovery on a backup created with *--backup*, so that it is ready to use. See preparing a backup. - **--print-defaults** Print the program argument list and exit. Must be given as the first option on the command-line. - **--print-param** Makes **xtrabackup** print out parameters that can be used for copying the data files back to their original locations to restore them. - **--read-buffer-size** Set the datafile read buffer size, given value is scaled up to page size. Default is 10Mb. - **--rebuild-indexes** Rebuilds indexes in a compact backup. This option only has effect when the *--prepare* and *--rebuild-threads* options are provided. - **--rebuild-threads=#** Uses the given number of threads to rebuild indexes in a compact backup. This option only has effect with the *--prepare* and *--rebuild-indexes* options. - **--remove-original** Implemented in *Percona XtraBackup* 2.4.6, this option when specified will remove **.qp**, **.xbcrypt** and **.qp.xbcrypt** files after decryption and decompression. - **--rocksdb-datadir** RocksDB data directory - **--rocksdb-wal-dir** RocksDB WAL directory. - **--rocksdb-checkpoint-max-age** The checkpoint cannot be older than this number of seconds when the backup completes. - **--rocksdb-checkpoint-max-count** Complete the backup even if the checkpoint age requirement has not been met after this number of checkpoints. - **--rollback-prepared-trx** Force rollback prepared InnoDB transactions. - **--rsync** Uses the **rsync** utility to optimize local file transfers. When this option is specified, *xtrabackup* uses **rsync** to copy all non-InnoDB files instead of spawning a separate **cp** for each file, which can be much faster for servers with a large number of databases or tables. This option cannot be used together with *--stream*. - **--safe-slave-backup** When specified, xtrabackup will stop the replica SQL thread just before running **FLUSH TABLES WITH READ LOCK** and wait to start backup until **Slave\_open\_temp\_tables** in **SHOW STATUS** is zero. If there are no open temporary tables, the backup will take place, otherwise the SQL thread will be started and stopped until there are no open temporary tables. The backup will fail if **Slave\_open\_temp\_tables** does not become zero after *--safe-slave-backup-timeout* seconds. The replication SQL thread will be restarted when the backup finishes. This option is implemented in order to deal with *replicating temporary tables* and isn't neccessary with Row-Based-Replication. - **--safe-slave-backup-timeout=SECONDS** How many seconds *--safe-slave-backup* should wait for **Slave\_open\_temp\_tables** to become zero. Defaults to 300 seconds. - **--secure-auth** Refuse client connecting to server if it uses old (pre-4.1.1) protocol. (Enabled by default; use --skip-secure-auth to disable.) - **--server-id=#** The server instance being backed up. - **--server-public-key-path** The file path to the server public RSA key in the PEM format. **SEE ALSO:** - ***MySQL* Documentation: The --server-public-key-path Option** *https://dev.mysql.com/doc/refman/8.0/en/connection-options.html#option\_general\_server-public-key-path* - **--skip-tables-compatibility-check** See *--tables-compatibility-check*. - **--slave-info** This option is useful when backing up a replication replica server. It prints the binary log position of the source server. It also writes the binary log coordinates to the **xtrabackup\_slave\_info** file as a **CHANGE MASTER** command. A new replica for this source can be set up by starting a replica server on this backup and issuing a **CHANGE MASTER** command with the binary log position saved in the **xtrabackup\_slave\_info** file. - **--socket** This option accepts a string argument that specifies the socket to use when connecting to the local database server with a UNIX domain socket. It is passed to the mysql child process without alteration. See **mysql** **--help** for details. - **--ssl** Enable secure connection. More information can be found in *--ssl* MySQL server documentation. - **--ssl-ca** Path of the file which contains list of trusted SSL CAs. More information can be found in *--ssl-ca* MySQL server documentation. - **--ssl-capath** Directory path that contains trusted SSL CA certificates in PEM format. More information can be found in *--ssl-capath* MySQL server documentation. - **--ssl-cert** Path of the file which contains X509 certificate in PEM format. More information can be found in *--ssl-cert* MySQL server documentation. - **--ssl-cipher** List of permitted ciphers to use for connection encryption. More information can be found in *--ssl-cipher* MySQL server documentation. - **--ssl-crl** Path of the file that contains certificate revocation lists. More information can be found in *--ssl-crl* MySQL server documentation. - **--ssl-crlpath** Path of directory that contains certificate revocation list files. More information can be found in *--ssl-crlpath* MySQL server documentation. - **--ssl-fips-mode** SSL FIPS mode (applies only for OpenSSL); permitted values are: *OFF*, *ON*, *STRICT*. - **--ssl-key** Path of file that contains X509 key in PEM format. More information can be found in *--ssl-key* MySQL server documentation. - **--ssl-mode** Security state of connection to server. More information can be found in *--ssl-mode* MySQL server documentation. - **--ssl-verify-server-cert** Verify server certificate Common Name value against host name used when connecting to server. More information can be found in *--ssl-verify-server-cert* MySQL server documentation. - **--stats** Causes **xtrabackup** to scan the specified data files and print out index statistics. - **--stream=FORMAT** Stream all backup files to the standard output in the specified format. Currently, this option only supports the *xbstream* format. - **--strict** If this option is specified, *xtrabackup* fails with an error when invalid parameters are passed. - **--tables=name** A regular expression against which the full tablename, in **databasename.tablename** format, is matched. If the name matches, the table is backed up. See partial backups. - **--tables-compatibility-check** Enables the engine compatibility warning. The default value is ON. To disable the engine compatibility warning use *--skip-tables-compatibility-check*. - **--tables-exclude=name** Filtering by regexp for table names. Operates the same way as *--tables*, but matched names are excluded from backup. Note that this option has a higher priority than *--tables*. - **--tables-file=name** A file containing one table name per line, in databasename.tablename format. The backup will be limited to the specified tables. - **--target-dir=DIRECTORY** This option specifies the destination directory for the backup. If the directory does not exist, **xtrabackup** creates it. If the directory does exist and is empty, **xtrabackup** will succeed. **xtrabackup** will not overwrite existing files, however; it will fail with operating system error 17, **file exists**. If this option is a relative path, it is interpreted as being relative to the current working directory from which **xtrabackup** is executed. In order to perform a backup, you need **READ**, **WRITE**, and **EXECUTE** permissions at a filesystem level for the directory that you supply as the value of *--target-dir*. - **--innodb-temp-tablespaces-dir=DIRECTORY** Directory where temp tablespace files live, this path can be absolute. - **--throttle=#** This option limits the number of chunks copied per second. The chunk size is *10 MB*. To limit the bandwidth to *10 MB/s*, set the option to *1*: *--throttle=1*. **SEE ALSO:** - **More information about how to throttle a backup** throttling\_backups - **--tls-ciphersuites** TLS v1.3 cipher to use. - **--tls-version** TLS version to use, permitted values are: *TLSv1*, *TLSv1.1*, *TLSv1.2*, *TLSv1.3*. - **--tmpdir=name** Specify the directory that will be used to store temporary files during the backup - **--transition-key=name** This option is used to enable processing the backup without accessing the keyring vault server. In this case, **xtrabackup** derives the AES encryption key from the specified passphrase and uses it to encrypt tablespace keys of tablespaces being backed up. If *--transition-key* does not have any value, **xtrabackup** will ask for it. The same passphrase should be specified for the *--prepare* command. - **--use-memory** This option affects how much memory is allocated for preparing a backup with *--prepare*, or analyzing statistics with *--stats*. Its purpose is similar to innodb\_buffer\_pool\_size. It does not do the same thing as the similarly named option in Oracle's InnoDB Hot Backup tool. The default value is 100MB, and if you have enough available memory, 1GB to 2GB is a good recommended value. Multiples are supported providing the unit (e.g. 1MB, 1M, 1GB, 1G). - **--user=USERNAME** This option specifies the MySQL username used when connecting to the server, if that's not the current user. The option accepts a string argument. See mysql --help for details. - **-v** See *--version* - **--version** This option prints *xtrabackup* version and exits. - **--xtrabackup-plugin-dir=DIRNAME** The absolute path to the directory that contains the **keyring** plugin. **SEE ALSO:** - ***Percona Server for MySQL* Documentation: keyring\_vault plugin with Data at Rest Encryption** *https://www.percona.com/doc/percona-server/LATEST/management/data\_at\_rest\_encryption.html#keyring-vault-plugin* - ***MySQL* Documentation: Using the keyring\_file File-Based Plugin** *https://dev.mysql.com/doc/refman/5.7/en/keyring-file-plugin.html* ## AUTHOR Percona LLC and/or its affiliates ## COPYRIGHT 2009-2022, Percona LLC and/or its affiliates