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Local alloc is a performance optimization in ocfs2 in which a node takes a window of bits from the global bitmap and then uses that for all small local allocations. This window size is fixed to 8MB currently. This patch allows users to specify the window size in MB including disabling it by passing in 0. If the number specified is too large, the fs will use the default value of 8MB. mount -o localalloc=X /dev/sdX /mntpoint Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
77 lines
2.9 KiB
Text
77 lines
2.9 KiB
Text
OCFS2 filesystem
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==================
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OCFS2 is a general purpose extent based shared disk cluster file
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system with many similarities to ext3. It supports 64 bit inode
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numbers, and has automatically extending metadata groups which may
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also make it attractive for non-clustered use.
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You'll want to install the ocfs2-tools package in order to at least
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get "mount.ocfs2" and "ocfs2_hb_ctl".
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Project web page: http://oss.oracle.com/projects/ocfs2
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Tools web page: http://oss.oracle.com/projects/ocfs2-tools
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OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/
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All code copyright 2005 Oracle except when otherwise noted.
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CREDITS:
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Lots of code taken from ext3 and other projects.
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Authors in alphabetical order:
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Joel Becker <joel.becker@oracle.com>
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Zach Brown <zach.brown@oracle.com>
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Mark Fasheh <mark.fasheh@oracle.com>
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Kurt Hackel <kurt.hackel@oracle.com>
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Sunil Mushran <sunil.mushran@oracle.com>
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Manish Singh <manish.singh@oracle.com>
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Caveats
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=======
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Features which OCFS2 does not support yet:
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- extended attributes
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- quotas
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- cluster aware flock
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- cluster aware lockf
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- Directory change notification (F_NOTIFY)
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- Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
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- POSIX ACLs
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Mount options
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=============
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OCFS2 supports the following mount options:
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(*) == default
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barrier=1 This enables/disables barriers. barrier=0 disables it,
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barrier=1 enables it.
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errors=remount-ro(*) Remount the filesystem read-only on an error.
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errors=panic Panic and halt the machine if an error occurs.
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intr (*) Allow signals to interrupt cluster operations.
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nointr Do not allow signals to interrupt cluster
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operations.
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atime_quantum=60(*) OCFS2 will not update atime unless this number
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of seconds has passed since the last update.
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Set to zero to always update atime.
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data=ordered (*) All data are forced directly out to the main file
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system prior to its metadata being committed to the
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journal.
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data=writeback Data ordering is not preserved, data may be written
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into the main file system after its metadata has been
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committed to the journal.
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preferred_slot=0(*) During mount, try to use this filesystem slot first. If
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it is in use by another node, the first empty one found
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will be chosen. Invalid values will be ignored.
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commit=nrsec (*) Ocfs2 can be told to sync all its data and metadata
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every 'nrsec' seconds. The default value is 5 seconds.
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This means that if you lose your power, you will lose
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as much as the latest 5 seconds of work (your
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filesystem will not be damaged though, thanks to the
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journaling). This default value (or any low value)
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will hurt performance, but it's good for data-safety.
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Setting it to 0 will have the same effect as leaving
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it at the default (5 seconds).
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Setting it to very large values will improve
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performance.
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localalloc=8(*) Allows custom localalloc size in MB. If the value is too
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large, the fs will silently revert it to the default.
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Localalloc is not enabled for local mounts.
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