Provided by: ocfs2-tools_1.8.5-3ubuntu1_amd64 
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) in that it allows users with limited read priviledges to query similar information. Users do not have to have the read privilege on the device as is expected by debugfs.ocfs2(8). This utility allows users to provide a path to an object on a mounted file system. The user needs to have the read priviledge 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) 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) 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-priviledged 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) fsck.ocfs2(8) fsck.ocfs2.checks(8) mkfs.ocfs2(8) mount.ocfs2(8) mounted.ocfs2(8) o2cluster(8) o2image(8) tunefs.ocfs2(8)
AUTHORS
Oracle Corporation
COPYRIGHT
Copyright © 2010, 2012 Oracle. All rights reserved.