--- name: "pmlogcompress" section: "1" platform: "linux" package: "pcp" version: "7.2.2-2" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/pmlogcompress" --- # pmlogcompress(1) compress and decompress PCP archive files ## NAME **pmlogcompress**, **pmlogdecompress** - compress and decompress PCP archive files ## SYNOPSIS **pmlogcompress** \[**-NV?**\] \[**-A** *arg*\] \[**-C** *conffile*\] \[**-c** *proglist*\] \[**-f** *prog*\] \[**-l** *limit*\] \[**-o** *type*\] \[**-Z** *min*\] *archive* ...\ **pmlogdecompress** \[**-NV?**\] \[**-t** *dir*\] *archive* ... ## DESCRIPTION **pmlogcompress** and **pmlogdecompress** support the compression and decompression of the files that make up a Performance Co-Pilot (PCP) archive; refer to [**LOGARCHIVE**(5)](/LOGARCHIVE/5.md) for an explanation of the various files that are components of a PCP archive. The *archive* arguments may be either the name of a single file in a PCP archive or the basename of a PCP archive, as in the style generated by [**pmlogbasename**(1)](/pmlogbasename/1.md). In the former case, **pmlogcompress** will compress (or **pmlogdecompress** will decompress) just that file, but in the latter case **pmlogcompress** will attempt to compress (or for **pmlogdecompress** to decompress) **all** the files that are part of the associated PCP archive. For decompression the suffix of the name of each file associated with *archive* determines the decompression tool to be used. ## OPTIONS The available command line options are: - **-A** *arg*, **--arg**=*arg* *arg* is used as an argument to the compression program; most likely useful with the **-f** option so that the choice of compression program is deterministic. The processing of *arg* is not sophisticated, so embedded shell variables, escape characters, shell \`\`glob'' characters and white space should be avoided. Multiple **-A** options are allowed and **all** the *arg* arguments will be used. - **-C** *conffile*, **--config**=*conffile* As described below variables that control the behaviour of **pmlogcompress** are defined in the configuration file *$PCP\_SYSCONF\_DIR/pmlogcompress/defaults*. The *-C* option allows for an alternate configuration file, *conffile*, to be used. - **-c** *proglist*, **--command**=*proglist* Depending on other command line options, and the availability of installed compression programs, the choice if program when compressing may vary. The **-c** option allows a **list** of compression programs to be provided, either with multiple **-c** options and/or by separating program names in *proglist* by a colon, in the style of the shell's **$PATH** notation. The default value for *proglist* is **zstd:xz:bzip2:gzip**. - **-f** *prog*, **--use**=*prog* If only one program is to be considered for compression then this may be specified using the **-f** option. The effect is the same as if only one **-c** option was used and *proglist* contained exactly one program name, namely *prog*. - **-l** *limit*, **--lower-limit**=*limit* When compressing, do not consider files smaller than *limit* (bytes). The default value for *limit* is 4096. - **-N**, **--show-me** Do nothing, but show what commands would have been executed. - **-o** *type*, **--optimize**=*type* When compressing the **-o** option will try to pick the compression program from *proglist* (see the **-c** option above) that does the \`\`best'' job, where *type* may be **space** to choose the compression program that produces the smallest output file, or **time** to choose the compression program that uses the least CPU time. If *archive* is an archive basename then the largest of the files that are part of the associated PCP archive is selected for the test, else *archive* will be used for the test. Use of this option means each of the selected *archive* files will be compressed multiple times, so it is likely that **-o** would be used in experiments with **-N** (and possibly **-V**) to determine the best compression tool for the local environment and PCP archives. - **-t** *dir*, **--dir**=*dir* When decompressing any compressed files will (by default) be replaced by their decompressed equivalent. The **-t** option changes this behavior to create a duplicate, uncompressed *archive* in the *dir* directory. If *archive* is a single file, then only that file is decompressed into *dir*, but if *archive* is an archive basename then **all** of the files of *archive* will be copied, and possibly decompressed, into *dir*. If a file is **not** compressed, then an attempt will first be made to create a hard link in *dir* with [**ln**(1)](/ln/1.md) and if this fails then a copy is made with [**cp**(1)](/cp/1.md). *dir* must exist before **pmlogdecompress** is run. - **-V**, **--verbose** Increase verbosity. - **-Z** *min*, **--min-zstd-size**=*min* [**xz**(1)](/xz/1.md) produces smaller compressed files for small input files, but at some point the input file becomes large enough that [**zstd**(1)](/zstd/1.md) produces smaller compressed files and **zstd** is typically much faster. When both **xz** and **xstd** are in consideration (see the **-c** option above), then the **-Z** option allows the user to tune where the **xz** to **zstd** cut-over happens; input files smaller than *min* (in bytes) will be compressed with **xz** else **zstd** will be used. The default value for *min* is 52428800 (50MiB). - **-?**, **--help** Display usage message and exit. ## NOTE For most users **pmlogcompress** and **pmlogdecompress** will not be used directly because explicit compression and decompression of PCP archives is not required. Rather, if archive compression is enabled, then this will be done indirectly from the PCP archive managements scripts [**pmlogger\_check**(1)](/pmlogger_check/1.md), [**pmlogger\_daily**(1)](/pmlogger_daily/1.md) and **pmlogger\_rewrite (1)** using **pmlogcompress**. Decompression is handled transparently during archive replay by the routines that implement the Performance Metrics Programming Interface (PMAPI). ## VARIABLES **pmlogcompress** uses a number of variables that can be used to customize the behaviour. Defaults are defined in the configuration file *$PCP\_SYSCONF\_DIR/pmlogcompress/defaults*, but these can be over-ridden by setting variables of the same name in the environment. And some command line options over-ride variables set in either the configuration file or the environment. The table below describes the variables and their equivalence to some of the command line options. | | | | | --- | --- | --- | | **Variable** | **Command line option** | | | **Description** | | PCP\_COMPRESS\_PROGS | **-c** *proglist* | | | A colon separated list of programs to be considered in turn. If only one program appears in the list, then all compression will consider using only that program. | | | **-f** *prog* | | | Short-hand for a *proglist* with just one *prog* in it. | | PCP\_COMPRESS\_MIN\_FILESIZE | **-l** *limit* | | | Archive files smaller than this will never be compressed. | | PCP\_COMPRESS\_ZSTD\_MIN\_FILESIZE | **-f** *prog* | | | Archive files smaller than this will never be compressed with [**zstd**(1)](/zstd/1.md). | | PCP\_COMPRESS\_ZSTD\_ARGS | **-A** *arg* **-f zstd** | | | Command line arguments to be used with [**zstd**(1)](/zstd/1.md). | | PCP\_COMPRESS\_XZ\_ARGS | **-A** *arg* **-f xz** | | | | Command line arguments to be used with [**xz**(1)](/xz/1.md). | | PCP\_COMPRESS\_BZIP2\_ARGS | **-A** *arg* **-f bzip2** | | | | Command line arguments to be used with [**bzip2**(1)](/bzip2/1.md). | | PCP\_COMPRESS\_GZIP\_ARGS | **-A** *arg* **-f gzip** | | | | Command line arguments to be used with [**gzip**(1)](/gzip/1.md). | ## FILES - *$PCP\_SYSCONF\_DIR/pmlogcompress/defaults* default settings for variables used by **pmlogcompress** ## PCP ENVIRONMENT Environment variables with the prefix **PCP\_** are used to parameterize the file and directory names used by PCP. On each installation, the file */etc/pcp.conf* contains the local values for these variables. The **$PCP\_CONF** variable may be used to specify an alternative configuration file, as described in [**pcp.conf**(4)](/pcp.conf/4.md). **pmlogcompress** has additional private variables with default values in *$PCP\_SYSCONF\_DIR/pmlogcompress/defaults* as described above. ## SEE ALSO [**PCPIntro**(1)](/PCPIntro/1.md), [**bzip2**(1)](/bzip2/1.md), [**gzip**(1)](/gzip/1.md), [**pmlogbasename**(1)](/pmlogbasename/1.md), [**pmlogger**(1)](/pmlogger/1.md), [**pmlogger\_check**(1)](/pmlogger_check/1.md), [**pmlogger\_daily**(1)](/pmlogger_daily/1.md), [**pmlogger\_rewrite**(1)](/pmlogger_rewrite/1.md), [**xz**(1)](/xz/1.md), [**zstd**(1)](/zstd/1.md), [**PMAPI**(3)](/PMAPI/3.md) and [**LOGARCHIVE**(5)](/LOGARCHIVE/5.md).