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Linux kernel mirror (for testing)
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linux
1OCFS2 filesystem
2==================
3OCFS2 is a general purpose extent based shared disk cluster file
4system with many similarities to ext3. It supports 64 bit inode
5numbers, and has automatically extending metadata groups which may
6also make it attractive for non-clustered use.
7
8You'll want to install the ocfs2-tools package in order to at least
9get "mount.ocfs2" and "ocfs2_hb_ctl".
10
11Project web page: http://oss.oracle.com/projects/ocfs2
12Tools web page: http://oss.oracle.com/projects/ocfs2-tools
13OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/
14
15All code copyright 2005 Oracle except when otherwise noted.
16
17CREDITS:
18Lots of code taken from ext3 and other projects.
19
20Authors in alphabetical order:
21Joel Becker <joel.becker@oracle.com>
22Zach Brown <zach.brown@oracle.com>
23Mark Fasheh <mark.fasheh@oracle.com>
24Kurt Hackel <kurt.hackel@oracle.com>
25Sunil Mushran <sunil.mushran@oracle.com>
26Manish Singh <manish.singh@oracle.com>
27
28Caveats
29=======
30Features which OCFS2 does not support yet:
31 - extended attributes
32 - quotas
33 - cluster aware flock
34 - cluster aware lockf
35 - Directory change notification (F_NOTIFY)
36 - Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
37 - POSIX ACLs
38
39Mount options
40=============
41
42OCFS2 supports the following mount options:
43(*) == default
44
45barrier=1 This enables/disables barriers. barrier=0 disables it,
46 barrier=1 enables it.
47errors=remount-ro(*) Remount the filesystem read-only on an error.
48errors=panic Panic and halt the machine if an error occurs.
49intr (*) Allow signals to interrupt cluster operations.
50nointr Do not allow signals to interrupt cluster
51 operations.
52atime_quantum=60(*) OCFS2 will not update atime unless this number
53 of seconds has passed since the last update.
54 Set to zero to always update atime.
55data=ordered (*) All data are forced directly out to the main file
56 system prior to its metadata being committed to the
57 journal.
58data=writeback Data ordering is not preserved, data may be written
59 into the main file system after its metadata has been
60 committed to the journal.
61preferred_slot=0(*) During mount, try to use this filesystem slot first. If
62 it is in use by another node, the first empty one found
63 will be chosen. Invalid values will be ignored.
64commit=nrsec (*) Ocfs2 can be told to sync all its data and metadata
65 every 'nrsec' seconds. The default value is 5 seconds.
66 This means that if you lose your power, you will lose
67 as much as the latest 5 seconds of work (your
68 filesystem will not be damaged though, thanks to the
69 journaling). This default value (or any low value)
70 will hurt performance, but it's good for data-safety.
71 Setting it to 0 will have the same effect as leaving
72 it at the default (5 seconds).
73 Setting it to very large values will improve
74 performance.
75localalloc=8(*) Allows custom localalloc size in MB. If the value is too
76 large, the fs will silently revert it to the default.
77 Localalloc is not enabled for local mounts.
78localflocks This disables cluster aware flock.
79inode64 Indicates that Ocfs2 is allowed to create inodes at
80 any location in the filesystem, including those which
81 will result in inode numbers occupying more than 32
82 bits of significance.
83user_xattr (*) Enables Extended User Attributes.
84nouser_xattr Disables Extended User Attributes.