Provided by: ocfs2-tools_1.8.6-2ubuntu1_amd64 bug

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 privileges 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 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) 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-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)    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.