o2info - Show OCFS2 file system information.

       Oracle Corporation

       Copyright © 2010, 2012 Oracle. All rights reserved.

Version 1.8.8                                     January 2012                                         o2info(1)

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.

       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--freefrag128/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%

       o2info - Show OCFS2 file system information.

       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.

-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.

       --freefragchunksize
              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.

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)

o2info  [-C|--cluster-coherent] [--fs-features] [--volinfo] [--mkfs] [--freeinode] [--freefragchunksize]
       [--space-usage] [--filestat] <deviceorfile>