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117 lines
4.7 KiB
117 lines
4.7 KiB
.. SPDX-License-Identifier: GPL-2.0 |
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================ |
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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://ocfs2.wiki.kernel.org |
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Tools git tree: https://github.com/markfasheh/ocfs2-tools |
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OCFS2 mailing lists: https://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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======= |
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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 <[email protected]> |
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- Zach Brown <[email protected]> |
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- Mark Fasheh <[email protected]> |
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- Kurt Hackel <[email protected]> |
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- Tao Ma <[email protected]> |
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- Sunil Mushran <[email protected]> |
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- Manish Singh <[email protected]> |
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- Tiger Yang <[email protected]> |
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Caveats |
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======= |
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Features which OCFS2 does not support yet: |
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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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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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======================= ======================================================== |
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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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noatime Do not update access time. |
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relatime(*) Update atime if the previous atime is older than |
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mtime or ctime |
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strictatime Always update atime, but the minimum update interval |
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is specified by atime_quantum. |
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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. This option need |
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work with strictatime. |
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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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localflocks This disables cluster aware flock. |
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inode64 Indicates that Ocfs2 is allowed to create inodes at |
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any location in the filesystem, including those which |
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will result in inode numbers occupying more than 32 |
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bits of significance. |
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user_xattr (*) Enables Extended User Attributes. |
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nouser_xattr Disables Extended User Attributes. |
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acl Enables POSIX Access Control Lists support. |
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noacl (*) Disables POSIX Access Control Lists support. |
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resv_level=2 (*) Set how aggressive allocation reservations will be. |
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Valid values are between 0 (reservations off) to 8 |
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(maximum space for reservations). |
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dir_resv_level= (*) By default, directory reservations will scale with file |
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reservations - users should rarely need to change this |
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value. If allocation reservations are turned off, this |
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option will have no effect. |
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coherency=full (*) Disallow concurrent O_DIRECT writes, cluster inode |
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lock will be taken to force other nodes drop cache, |
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therefore full cluster coherency is guaranteed even |
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for O_DIRECT writes. |
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coherency=buffered Allow concurrent O_DIRECT writes without EX lock among |
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nodes, which gains high performance at risk of getting |
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stale data on other nodes. |
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journal_async_commit Commit block can be written to disk without waiting |
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for descriptor blocks. If enabled older kernels cannot |
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mount the device. This will enable 'journal_checksum' |
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internally. |
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======================= ========================================================
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