.TH "o2info" "1" "January 2012" "Version 1.8.7" "OCFS2 Manual Pages"
.SH "NAME"
o2info \- Show \fIOCFS2\fR file system information.
.SH "SYNOPSIS"
\fBo2info\fR [\fB\-C|\-\-cluster\-coherent\fR] [\fB\-\-fs\-features\fR] [\fB\-\-volinfo\fR] [\fB\-\-mkfs\fR] [\fB\-\-freeinode\fR] [\fB\-\-freefrag\fR \fIchunksize\fR] [\fB\-\-space\-usage\fR] [\fB\-\-filestat\fR] <\fBdevice or file\fR>

.SH "DESCRIPTION"
.PP
\fBo2info\fR shows information about \fIOCFS2\fR file systems. It differs from \fBdebugfs.ocfs2(8)\fR
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 \fBdebugfs.ocfs2(8)\fR. 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.

.SH "OPTIONS"
.TP
\fB\-C, \-\-cluster\-coherent\fR
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.

.TP
\fB\-\-fs\-features\fR
Show all the file system features (compat, incompat, ro compat) enabled on the file system.

.TP
\fB\-\-volinfo\fR
Show file system information such as label, uuid, block and cluster sizes, node slots, etc.

.TP
\fB\-\-mkfs\fR
Show file system information in \fBmkfs.ocfs2(8)\fR format.

.TP
\fB\-\-freeinode\fR
Show the inode (allocated/free) count for all slots in the file system.

.TP
\fB\-\-freefrag\fR \fIchunksize\fR
Show the free space fragmentation of the file system. The chunksize should be equal to or
greater than the cluster size.

.TP
\fB\-\-space\-usage\fR
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.

.TP
\fB\-\-filestat\fR
Show the extended \fBstat(1)\fR information that includes the number of clusters consumed
by extended attributes, unwritten extents, shared extents and holes, along with the file
fragmentation score.

.TP
\fB\-V, \-\-version\fR
Show version and exit.

.TP
\fB\-h, \-\-help\fR
Show help and exit.

.SH "NOTE"
.PP
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
\fIOCFS2\fR file systems running on systems having older kernels.

.SH "EXAMPLES"
.PP
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.

.in +4n
.nf
# \fBo2info --volinfo /ocfs2/testfile\fR
       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
.fi
.in

The same goes for querying file system fragmentation.

.in +4n
.nf
# \fBo2info --freefrag 128 /ocfs2/testfile\fR
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%
.fi
.in

.SH "SEE ALSO"
.BR debugfs.ocfs2(8)
.BR fsck.ocfs2(8)
.BR fsck.ocfs2.checks(8)
.BR mkfs.ocfs2(8)
.BR mount.ocfs2(8)
.BR mounted.ocfs2(8)
.BR o2cluster(8)
.BR o2image(8)
.BR tunefs.ocfs2(8)

.SH "AUTHORS"
Oracle Corporation

.SH "COPYRIGHT"
Copyright \(co 2010, 2012 Oracle. All rights reserved.