---
name: "o2info"
section: "1"
platform: "linux"
package: "ocfs2-tools"
version: "1.8.8-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/o2info"
---

# o2info(1)

Show OCFS2 file system information.

## NAME

o2info - Show *OCFS2* file system information.

## SYNOPSIS

**o2info** \[**-C\|--cluster-coherent**\] \[**--fs-features**\] \[**--volinfo**\] \[**--mkfs**\] \[**--freeinode**\] \[**--freefrag** *chunksize*\] \[**--space-usage**\] \[**--filestat**\] \<**device or file**\>

## DESCRIPTION

**o2info** shows information about *OCFS2* file systems. It differs from **[debugfs.ocfs2(8)](/debugfs.ocfs2/8.md)** in that it allows users with limited read privileges to query similar information. Users do not have to have the read privilege on the device as is expected by **[debugfs.ocfs2(8)](/debugfs.ocfs2/8.md)**. This utility allows users to provide a path to an object on a mounted file system. The user needs to have the read privilege on that object.

## OPTIONS

- **-C, --cluster-coherent**

  Force cluster coherency when querying a mounted file systems. The is disabled by default. Enable this only if accurate information is required as it involves taking cluster locks.

- **--fs-features**

  Show all the file system features (compat, incompat, ro compat) enabled on the file system.

- **--volinfo**

  Show file system information such as label, uuid, block and cluster sizes, node slots, etc.

- **--mkfs**

  Show file system information in **[mkfs.ocfs2(8)](/mkfs.ocfs2/8.md)** format.

- **--freeinode**

  Show the inode (allocated/free) count for all slots in the file system.

- **--freefrag** *chunksize*

  Show the free space fragmentation of the file system. The chunksize should be equal to or greater than the cluster size.

- **--space-usage**

  Show the disk space used by a file in block sized units. It also provides the block count of the holes, shared extents and unwritten extents.

- **--filestat**

  Show the extended **[stat(1)](/stat/1.md)** information that includes the number of clusters consumed by extended attributes, unwritten extents, shared extents and holes, along with the file fragmentation score.

- **-V, --version**

  Show version and exit.

- **-h, --help**

  Show help and exit.

## NOTE

The utility uses custom info ioctls to query information from a mounted file system. As these info ioctls were added starting in Linux kernel 2.6.37, this utility will not work on mounted *OCFS2* file systems running on systems having older kernels.

## EXAMPLES

Non-privileged users can query the volume information by providing the path to a file on a mounted file system. Priviledged users can provide the path to the device.

```
# o2info --volinfo /ocfs2/testfile
       Label: webhome
        UUID: 8AB016CD59FC4327A2CDAB69F08518E3
  Block Size: 4096
Cluster Size: 131072
  Node Slots: 8
    Features: backup-super strict-journal-super sparse extended-slotmap
    Features: inline-data xattr indexed-dirs refcount discontig-bg clusterinfo
    Features: unwritten
```

The same goes for querying file system fragmentation.

```
# o2info --freefrag 128 /ocfs2/testfile
Blocksize: 4096 bytes
Clustersize: 131072 bytes
Total clusters: 409599
Free clusters: 376537 (91.92%)
Min. free extent: 256 KB
Max. free extent: 4091648 KB
Avg. free extent: 172672 KB
Chunksize: 131072 bytes (1 clusters)
Total chunks: 409600
Free chunks: 376537 (91.9%)
HISTOGRAM OF FREE EXTENT SIZES:
Extent Size Range :  Free extents  Free Clusters  Percent
  256K...  512K-  :             4            10    0.00%
  512K... 1024K-  :           251          1179    0.31%
    1M...    2M-  :             5            72    0.02%
    8M...   16M-  :             3           288    0.08%
   32M...   64M-  :             1           447    0.12%
  128M...  256M-  :             2          3371    0.90%
    1G...    2G-  :             1         13823    3.67%
    2G...    4G-  :            12        357347   94.90%
```

## SEE ALSO

**[debugfs.ocfs2(8)](/debugfs.ocfs2/8.md)** **[fsck.ocfs2(8)](/fsck.ocfs2/8.md)** **[fsck.ocfs2.checks(8)](/fsck.ocfs2.checks/8.md)** **[mkfs.ocfs2(8)](/mkfs.ocfs2/8.md)** **[mount.ocfs2(8)](/mount.ocfs2/8.md)** **[mounted.ocfs2(8)](/mounted.ocfs2/8.md)** **[o2cluster(8)](/o2cluster/8.md)** **[o2image(8)](/o2image/8.md)** **[tunefs.ocfs2(8)](/tunefs.ocfs2/8.md)**

## AUTHORS

Oracle Corporation

## COPYRIGHT

Copyright © 2010, 2012 Oracle. All rights reserved.