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diff --git a/Documentation/filesystems/ocfs2.rst b/Documentation/filesystems/ocfs2.rst new file mode 100644 index 000000000..42ca9a3d4 --- /dev/null +++ b/Documentation/filesystems/ocfs2.rst @@ -0,0 +1,117 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================ +OCFS2 filesystem +================ + +OCFS2 is a general purpose extent based shared disk cluster file +system with many similarities to ext3. It supports 64 bit inode +numbers, and has automatically extending metadata groups which may +also make it attractive for non-clustered use. + +You'll want to install the ocfs2-tools package in order to at least +get "mount.ocfs2" and "ocfs2_hb_ctl". + +Project web page: http://ocfs2.wiki.kernel.org +Tools git tree: https://github.com/markfasheh/ocfs2-tools +OCFS2 mailing lists: https://oss.oracle.com/projects/ocfs2/mailman/ + +All code copyright 2005 Oracle except when otherwise noted. + +Credits +======= + +Lots of code taken from ext3 and other projects. + +Authors in alphabetical order: + +- Joel Becker <joel.becker@oracle.com> +- Zach Brown <zach.brown@oracle.com> +- Mark Fasheh <mfasheh@suse.com> +- Kurt Hackel <kurt.hackel@oracle.com> +- Tao Ma <tao.ma@oracle.com> +- Sunil Mushran <sunil.mushran@oracle.com> +- Manish Singh <manish.singh@oracle.com> +- Tiger Yang <tiger.yang@oracle.com> + +Caveats +======= +Features which OCFS2 does not support yet: + + - Directory change notification (F_NOTIFY) + - Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease) + +Mount options +============= + +OCFS2 supports the following mount options: + +(*) == default + +======================= ======================================================== +barrier=1 This enables/disables barriers. barrier=0 disables it, + barrier=1 enables it. +errors=remount-ro(*) Remount the filesystem read-only on an error. +errors=panic Panic and halt the machine if an error occurs. +intr (*) Allow signals to interrupt cluster operations. +nointr Do not allow signals to interrupt cluster + operations. +noatime Do not update access time. +relatime(*) Update atime if the previous atime is older than + mtime or ctime +strictatime Always update atime, but the minimum update interval + is specified by atime_quantum. +atime_quantum=60(*) OCFS2 will not update atime unless this number + of seconds has passed since the last update. + Set to zero to always update atime. This option need + work with strictatime. +data=ordered (*) All data are forced directly out to the main file + system prior to its metadata being committed to the + journal. +data=writeback Data ordering is not preserved, data may be written + into the main file system after its metadata has been + committed to the journal. +preferred_slot=0(*) During mount, try to use this filesystem slot first. If + it is in use by another node, the first empty one found + will be chosen. Invalid values will be ignored. +commit=nrsec (*) Ocfs2 can be told to sync all its data and metadata + every 'nrsec' seconds. The default value is 5 seconds. + This means that if you lose your power, you will lose + as much as the latest 5 seconds of work (your + filesystem will not be damaged though, thanks to the + journaling). This default value (or any low value) + will hurt performance, but it's good for data-safety. + Setting it to 0 will have the same effect as leaving + it at the default (5 seconds). + Setting it to very large values will improve + performance. +localalloc=8(*) Allows custom localalloc size in MB. If the value is too + large, the fs will silently revert it to the default. +localflocks This disables cluster aware flock. +inode64 Indicates that Ocfs2 is allowed to create inodes at + any location in the filesystem, including those which + will result in inode numbers occupying more than 32 + bits of significance. +user_xattr (*) Enables Extended User Attributes. +nouser_xattr Disables Extended User Attributes. +acl Enables POSIX Access Control Lists support. +noacl (*) Disables POSIX Access Control Lists support. +resv_level=2 (*) Set how aggressive allocation reservations will be. + Valid values are between 0 (reservations off) to 8 + (maximum space for reservations). +dir_resv_level= (*) By default, directory reservations will scale with file + reservations - users should rarely need to change this + value. If allocation reservations are turned off, this + option will have no effect. +coherency=full (*) Disallow concurrent O_DIRECT writes, cluster inode + lock will be taken to force other nodes drop cache, + therefore full cluster coherency is guaranteed even + for O_DIRECT writes. +coherency=buffered Allow concurrent O_DIRECT writes without EX lock among + nodes, which gains high performance at risk of getting + stale data on other nodes. +journal_async_commit Commit block can be written to disk without waiting + for descriptor blocks. If enabled older kernels cannot + mount the device. This will enable 'journal_checksum' + internally. +======================= ======================================================== |