Ubuntu Manpage: mount.ocfs2 - mount an OCFS2 filesystem

NAME

       mount.ocfs2 -  mount an OCFS2 filesystem

SYNOPSIS

       mount.ocfs2 [-vn] [-o options] device dir

DESCRIPTION

       mount.ocfs2  mounts  an  OCFS2  filesystem at dir. It is usually invoked indirectly by the
       mount(8) command.

OPTIONS

_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.

NOTES

       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
        ...

AUTHORS

       Oracle Corporation

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