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o2info(1)		      OCFS2 Manual Pages		     o2info(1)

NAME
       o2info - Dump OCFS2 file system information on disk.

SYNOPSIS
       o2info  [-C|--cluster-coherent]	[--fs-features]	 [--volinfo]  [--mkfs]
       [--freeinode]  [--freefrag  chunksize]	[--space-usage]	  [--filestat]
       <device or file>

DESCRIPTION
       o2info  is  designed  to	 be an information tool, to display OCFS2 file
       system information on disk. Its main goal on one hand, is to provide  a
       tool to display fs info in a comprehensive way and providing the infor‐
       mation which may be missing in debugfs.ocfs and	tunefs.ocfs2  such  as
       global  bitmap  free  space  fragmentation and free inode info for each
       slot, on the other hand, it also aims to	 become	 a  info  tool(not  an
       administration  one),  which therefore allows all users who may have no
       read privilege on the underlying device to use the  utility.  In	 prac‐
       tice,  'o2info  /path/to/file/on/ocfs2/vol'  use	 a  new OCFS2_IOC_INFO
       ioctl to get info  from	fs  for	 a  mounted  case.  For	 a  privileged
       user(e.g, root), the same info however, can also be accessed by 'o2info
       /dev/sdxN' to direcly manipulate the raw device.

OPTIONS
       -C, --cluster-coherent
	      Enable cluster (in)coherency for mounted	case,  means  it  will
	      attempt  to  acquire  a global PR lock when querying info from a
	      cluster filesystem, which may degrade the	 performance,  default
	      is none cluster-coherency.

       --fs-features
	      List  all	 compat,  incompat  and ro-compat fs features on OCFS2
	      filesystem.

       --volinfo
	      Dump basic volume information, such as  blocksize,  clustersize,
	      volume label and UUID etc.

       --mkfs Dump  an	original format of mkfs.ocfs's arguments, importantly,
	      which can be used directly as a fresh  mkfs  retry:  #mkfs.ocfs2
	      "$(o2info --mkfs /dev/name/or/path/of/file)" /dev/sdaX

       --freeinode
	      Display free inode space for all nodes in OCFS2 cluster.

       --freefrag chunksize
	      Report  free space fragmentation on OCFS2 filesystems, it prints
	      how many chunks of chunksize are	available  as  contiguous  and
	      aligned  free space by scanning the global allocation bitmap. In
	      the meantime, the percentage of contiguous free clusters of size
	      and  of  alignment  chunksize  is reported, what's more, it also
	      displays the minimum/maximum/average free chunk size in filesys‐
	      tem,  along with a histogram of all free chunks. NOTE, chunksize
	      specified must be a power of two and be equal to or larger  than
	      filesystem's clustersize.

       --space-usage
	      Display  file's  usage  information on disk in terms of how many
	      physical blocks it consumed, how many reserved space  and	 holes
	      in it.

       --filestat
	      Display  inode's	standard stat information, other than this, it
	      also dumps inode's extended info such as extents, fragmentation,
	      holes, unwritten and shared space in clusters.

       -V, --version
	      Show version and exit.

       -h, --help
	      Display help and exit.

EXAMPLES
       [oracle@node1  ~]#  o2info --volinfo /storage/testfile	   # For none-
       privileged users.
       [root@node1 ~]# o2info --volinfo /dev/sda1
	      Label: ocfs2-volume
	       UUID: 976D8E630B3A4F1F95497311A92901FC
	 Block Size: 4096
       Cluster Size: 4096
	 Node Slots: 4
	   Features:  backup-super  strict-journal-super  sparse   inline-data
       xattr
	   Features: unwritten

       [oracle@node1  ~]#  o2info  --freefrag  64 /storage/testfile	 # For
       none-privileged users.
       [root@node1 ~]# o2info --freefrag 64 /dev/sda1
       Blocksize: 4096 bytes
       Clustersize: 32768 bytes
       Total clusters: 915704
       Free clusters: 891687 (97.4%)

       Min. free extent: 32 KB
       Max. free extent: 1032160 KB
       Avg. free extent: 663552 KB

       Chunksize: 131072 bytes (4 clusters)
       Total chunks: 228927
       Free chunks: 222888 (97.4%)

       HISTOGRAM OF FREE EXTENT SIZES:
       Extent Size Range :  Free extents  Free Clusters	 Percent
	  32K...   64K-	 :	       1	     1	  0.00%
	   1M...    2M-	 :	       9	   288	  0.03%
	   8M...   16M-	 :	       2	   831	  0.09%
	  32M...   64M-	 :	       1	  2047	  0.23%
	 128M...  256M-	 :	       1	  8191	  0.92%
	 256M...  512M-	 :	       2	 21706	  2.43%
	 512M... 1024M-	 :	      27	858623	 96.29%

SEE ALSO
       debugfs.ocfs2(8) tunefs.ocfs2(8)

AUTHORS
       Oracle Corporation

COPYRIGHT
       Copyright © 2010 Oracle. All rights reserved.

Version 1.8.0			 October 2010			     o2info(1)

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