mount.ocfs2 - mount an OCFS2 filesystem
mount.ocfs2 [-vn] [-o options] device
dir
mount.ocfs2 mounts an OCFS2 filesystem at
dir. It is usually invoked indirectly by the mount(8)
command.
- _netdev
- Indicates that the file system resides on a device that requires network
access (used to prevent the system from attempting to mount these
filesystems until the network has been enabled on the system).
mount.ocfs2(8) transparently appends this option during mount.
However, users mounting the volume via /etc/fstab must explicitly specify
this mount option to delay the system from mounting the volume until after
the network has been enabled.
- noatime
- The file system will not update access time.
- relatime
- The file system will update atime only if the on-disk atime is older than
mtime or ctime. This is the default mode.
- strictatime,atime_quantum=nrsec
- The file system will always perform atime updates, but the minimum update
interval is specified by atime_quantum which defaults to 60 secs. Set it
to zero to always update atime. These two options need work together.
- [no]acl
- Enables / disables POSIX ACLs (access control lists) support. It is
enabled by default.
- [no]user_xattr
- Enables / disables extended user attributes. It is enabled by default.
- commit=nrsec
- Sync all data and metadata every nrsec seconds. The default value is 5
seconds. Zero means default.
- data=[ordered|writeback]
- Specifies the handling of file data during metadata journalling.
- ordered
- This is the default mode. Data is flushed to disk before the corresponding
meta-data is committed to the journal.
- writeback
- Data ordering is not preserved - data may be flushed to disk after the
corresponding meta-data is committed to the journal. This is rumored to be
the higher-throughput option. While it guarantees internal file system
integrity, it can allow old data to appear in files after a crash and
journal recovery.
- errors=[remount-ro|errors=panic|errors=continue]
- Specifies the behavior when an on-disk corruption is encountered.
- remount-ro
- This is the default mode. The file system is remounted read-only.
- panic
- The system is halted via panic.
- continue
- Ignore errors. Just log error message, return error code to the calling
process and continue.
- localflocks
- This disables cluster-aware flock(2).
- coherency=[full|coherency]
- Specifies the extent of coherency for the cached file data across the
cluster. This mount option works with Linux kernel 2.6.37 and
later.
- full
- This is the default mode. The file system ensures the cached file data is
coherent across the cluster for all IO modes.
- buffered
- The file system only ensures the cached file data coherency for buffered
mode IOs. It does not perform IO serialization for direct IOs. This allows
multiple nodes to perform concurrent direct IOs to the same file. This is
the recommended mode for volumes hosting database files.
- resv_level=level
- Specifies the level of allocation reservation for files. The higher the
value, the more aggressive it is. Valid values are between 0 (reservation
off) to 8 (maximum space for reservation). It defaults to 2. This mount
option works with Linux kernel 2.6.35 and later.
- dir_resv_level=level
- By default, directory reservation scales with file reserveration. Users
should rarely need to change this value. If the file allocation
reservation is turned off, this option will have no effect. This mount
option works with Linux kernel 2.6.35 and later.
- inode64
- Indicates that the file system can create inodes at any location in the
volume, including those which will result in inode numbers greater than 4
billion.
- nocluster
- This option allows users to mount a clustered volume without configuring
the cluster stack. However, you must be aware that you can only mount the
file system from one node at the same time, otherwise, the file system may
be damaged. Please use it with caution.
- [no]intr
- Specifies whether a signal can interrupt IOs. It is disabled by default.
- ro
- Mount the file system read-only.
- rw
- Mount the file system read-write.
To mount and umount a OCFS2 volume, do:
# mount /dev/sda1 /mount/path
...
# umount /mount/path
Users mounting a clustered volume should be aware of the
following:
1. The cluster stack must to be online for a clustered mount to succeed.
2. The clustered mount operation is not instantaneous; it must
wait for the node to join the DLM domain.
3. Likewise, clustered umount is also not instantaneous; it
involves migrating all mastered lock-resources to the other nodes in the
cluster.
If the mount fails, detailed errors can be found via
dmesg(8). These might include incorrect cluster configuration (say, a
missing node or incorrect IP address) or a firewall interfering with
o2cb network traffic. Check the configuration as listed in
o2cb(7) or the man page of the active cluster stack.
To auto-mount volumes on startup, the file system tools include an
ocfs2 init service. This runs after the o2cb init service has
started the cluster. The ocfs2 init service mounts all OCFS2
volumes listed in /etc/fstab.
# chkconfig --add o2cb
o2cb 0:off 1:off 2:on 3:on 4:off 5:on 6:off
$ chkconfig --add ocfs2
o2cb 0:off 1:off 2:on 3:on 4:off 5:on 6:off
$ cat /etc/fstab
...
/dev/sda1 /u01 ocfs2 _netdev,defaults 0 0
...
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