o2info

o2info(1) OCFS2 Manual Pages o2info(1)

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%