Documentation/filesystems/ocfs2.txt

   1 OCFS2 filesystem
   2 ==================
   3 OCFS2 is a general purpose extent based shared disk cluster file
   4 system with many similarities to ext3. It supports 64 bit inode
   5 numbers, and has automatically extending metadata groups which may
   6 also make it attractive for non-clustered use.
   7
   8 You'll want to install the ocfs2-tools package in order to at least
   9 get "mount.ocfs2" and "ocfs2_hb_ctl".
  10
  11 Project web page:    http://oss.oracle.com/projects/ocfs2
  12 Tools web page:      http://oss.oracle.com/projects/ocfs2-tools
  13 OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/
  14
  15 All code copyright 2005 Oracle except when otherwise noted.
  16
  17 CREDITS:
  18 Lots of code taken from ext3 and other projects.
  19
  20 Authors in alphabetical order:
  21 Joel Becker   <joel.becker@oracle.com>
  22 Zach Brown    <zach.brown@oracle.com>
  23 Mark Fasheh   <mark.fasheh@oracle.com>
  24 Kurt Hackel   <kurt.hackel@oracle.com>
  25 Sunil Mushran <sunil.mushran@oracle.com>
  26 Manish Singh  <manish.singh@oracle.com>
  27
  28 Caveats
  29 =======
  30 Features which OCFS2 does not support yet:
  31         - quotas
  32         - Directory change notification (F_NOTIFY)
  33         - Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
  34         - POSIX ACLs
  35
  36 Mount options
  37 =============
  38
  39 OCFS2 supports the following mount options:
  40 (*) == default
  41
  42 barrier=1               This enables/disables barriers. barrier=0 disables it,
  43                         barrier=1 enables it.
  44 errors=remount-ro(*)    Remount the filesystem read-only on an error.
  45 errors=panic            Panic and halt the machine if an error occurs.
  46 intr            (*)     Allow signals to interrupt cluster operations.
  47 nointr                  Do not allow signals to interrupt cluster
  48                         operations.
  49 atime_quantum=60(*)     OCFS2 will not update atime unless this number
  50                         of seconds has passed since the last update.
  51                         Set to zero to always update atime.
  52 data=ordered    (*)     All data are forced directly out to the main file
  53                         system prior to its metadata being committed to the
  54                         journal.
  55 data=writeback          Data ordering is not preserved, data may be written
  56                         into the main file system after its metadata has been
  57                         committed to the journal.
  58 preferred_slot=0(*)     During mount, try to use this filesystem slot first. If
  59                         it is in use by another node, the first empty one found
  60                         will be chosen. Invalid values will be ignored.
  61 commit=nrsec    (*)     Ocfs2 can be told to sync all its data and metadata
  62                         every 'nrsec' seconds. The default value is 5 seconds.
  63                         This means that if you lose your power, you will lose
  64                         as much as the latest 5 seconds of work (your
  65                         filesystem will not be damaged though, thanks to the
  66                         journaling).  This default value (or any low value)
  67                         will hurt performance, but it's good for data-safety.
  68                         Setting it to 0 will have the same effect as leaving
  69                         it at the default (5 seconds).
  70                         Setting it to very large values will improve
  71                         performance.
  72 localalloc=8(*)         Allows custom localalloc size in MB. If the value is too
  73                         large, the fs will silently revert it to the default.
  74                         Localalloc is not enabled for local mounts.
  75 localflocks             This disables cluster aware flock.
  76 inode64                 Indicates that Ocfs2 is allowed to create inodes at
  77                         any location in the filesystem, including those which
  78                         will result in inode numbers occupying more than 32
  79                         bits of significance.
  80 user_xattr      (*)     Enables Extended User Attributes.
  81 nouser_xattr            Disables Extended User Attributes.