.RS 4
Get the LFSCK global status via the specified MDT device.
.RE
+.SS BARRIER
+The tools set for write (modify) barrier on all MDTs.
+.TP
+.B barrier_freeze \fR<fsname> [timeout]
+.br
+Set write barrier on all MDTs. The barrier_freeze command will not return
+until the barrier is set (frozen) or failed. With the write barrier set,
+any subsequent metadata modification will be blocked until the barrier is
+thawed or expired. The barrier lifetime is started when triggering
+barrier_freeze, and will be terminated when barrier thawed. To avoid the
+system being frozen for very long time if miss/fail to call barrier_thaw,
+you can specify its lifetime via the 'timeout' parameter in second, the
+default value is 60 (seconds). If the barrier is not thawed before that,
+it will be expired automatically.
+A barrier_freeze can only succeed when all registered MDTs are available.
+If some MDT has ever registered but become offline, then barrier_freeze
+will fail. To check and update current status of MDTs, see the command
+barrier_rescan.
+.TP
+.B barrier_thaw \fR<fsname>
+.br
+Reset write barrier on all MDTs. With the write barrier thawed, all blocked
+metadata modifications (by the former barrier_freeze) will be handled normally.
+.TP
+.B barrier_stat \fR<fsname>
+.br
+Query the write barrier status, the possible status and related meanings are
+as following:
+.br
+ 'init': has never set barrier on the system
+ 'freezing_p1': in the first stage of setting the write barrier
+ 'freezing_p2': in the second stage of setting the write barrier
+ 'frozen': the write barrier has been set successfully
+ 'thawing': in thawing the write barrier
+ 'thawed': the write barrier has been thawed
+ 'failed': fail to set write barrier
+ 'expired': the write barrier is expired
+ 'rescan': in scanning the MDTs status, see the command barrier_rescan
+ 'unknown': other cases
+.br
+If the barrier is in 'freezing_p1', 'freezing_p2' or 'frozen' status, then
+the left lifetime will be returned also.
+.TP
+.B barrier_rescan \fR<fsname> [timeout]
+.br
+Scan the system to check which MDTs are active. The status of the MDTs is
+required because a barrier_freeze will be unsuccessful if any of the MDTs
+are permenantly offline. During barrier_rescan, the MDT status is updated.
+If an MDT does not respond the barrier_rescan within the given "timeout"
+seconds (where the default value is 60 seconds), then it will be marked
+as unavailable or inactive.
+
+.SS SNAPSHOT
+ZFS backend based snapshot tools set. The tool loads system configuration
+from the file /etc/ldev.conf on the MGS, and call related ZFS commands to
+maintain Lustre snapshot pieces on all targets (MGS/MDT/OST).
+The configuration file /etc/ldev.conf is not only for snapshot, but also
+for other purpose. The format is:
+ <host> foreign/- <label> <device> [journal-path]/- [raidtab]
+
+The format of <label> is:
+ fsname-<role><index> or <role><index>
+
+The format of <device> is:
+ [md|zfs:][pool_dir/]<pool>/<filesystem>
+
+Snapshot only uses the fields <host>, <label> and <device>.
+.br
+.B Example:
+.br
+.B
+# cat /etc/ldev.conf
+.br
+ host-mdt1 - myfs-MDT0000 zfs:/tmp/myfs-mdt1/mdt1
+ host-mdt2 - myfs-MDT0001 zfs:myfs-mdt2/mdt2
+ host-ost1 - OST0000 zfs:/tmp/myfs-ost1/ost1
+ host-ost2 - OST0001 zfs:myfs-ost2/ost2
+
+For old snasphot tools, the configration is in /etc/lsnapshot/${fsname}.conf,
+the format is as following (per target, per line):
+ <host> <pool_dir> <pool> <local_filesystem> <role(,s)> <index>
+.br
+.B Examples:
+.br
+.B
+# cat /etc/lsnapshot/testfs.conf
+.br
+ VM6_1 /tmp testfs-mdt1 mdt1 MGS,MDT 0
+ VM6_2 /tmp testfs-mdt2 mdt2 MDT 1
+ VM6_3 /tmp testfs-ost1 ost1 OST 0
+ VM6_3 /tmp testfs-ost2 ost2 OST 1
+ VM6_4 /tmp testfs-ost3 ost3 OST 2
+ VM6_4 /tmp testfs-ost4 ost4 OST 3
+
+.TP
+.B snapshot_create \fR[-b | --barrier [on | off]] [-c | --comment comment]
+ \fR<-F | --fsname fsname> [-h | --help] <-n | --name ssname>
+ \fR[-r | --rsh remote_shell] [-t | --timeout timeout]
+.br
+Create snapshot with the given name.
+.TP
+ -b, --barrier [on | off]
+Set write barrier on all MDTs before creating the snapshot. The default behavior
+is 'on'. If you are confident about the system consistency, or you do not care
+about the system consistency when create the snapshot, then you can specify
+barrier 'off'. That will save your time of creating the snapshot. If the barrier
+is 'on', then the timeout of the barrier can be specified via '-t' option as
+described in the subsequent section.
+.TP
+ -c, --comment <comment>
+Add an optional comment to the snapshot_create request. The comment can include
+anything to describe what the snapshot is for or for reminder. The comment can
+be shown via snapshot_list.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot's name must be specified. It follows the general ZFS snapshot name
+rules, such as the max length is 256 bytes, cannot be conflict with the reserved
+names, and so on.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
+.TP
+ -t, --timeout <timeout>
+If write barrier is 'on', then the 'timeout' specified the write barrier's
+lifetime in second. The default vaule is 60 (seconds).
+.TP
+.B snapshot_destroy \fR[-f | --force] <-F | --fsname fsname> [-h | --help]
+ \fR<-n | --name ssname> [-r | --rsh remote_shell]
+.br
+Destroy the specified snapshot.
+.TP
+ -f, --force
+Destory the specified snapshot by force. If the snapshot is mounted, it will be
+umounted firstly, then destroyed. Even if some pieces of the snapshot are lost
+or broken for some reason(s), the remained parts of the snapshot still can be
+destroyed with this option specified.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot (to be destroyed) name must be specified.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
+.TP
+.B snapshot_modify \fR[-c | --comment comment] <-F | --fsname fsname>
+ \fR[-h | --help] <-n | --name ssname> [-N | --new new_ssname]
+ \fR[-r | --rsh remote_shell]
+.br
+Modify the specified snapshot.
+.TP
+ -c, --comment <comment>
+Add comment (if it has not been specified when snapshot_create) or change the
+comment for the given snapshot.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot (to be modified) name must be specified.
+.TP
+ -N, --new <new_ssname>
+Rename the snapshot to the new name. It follows the general ZFS snapshot name
+rules, such as the max length is 256 bytes, cannot be conflict with the reserved
+names, and so on.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
+.TP
+.B snapshot_list \fR[-d | --detail] <-F | --fsname fsname> [-h | --help]
+ \fR[-n | --name ssname] [-r | --rsh remote_shell]
+.br
+Query the snapshot information, such as fsname of the snapshot, comment,
+create time, the latest modification time, whether mounted or not, and so on.
+.TP
+ -d, --detail
+List all the information available for each piece of the snapshot on each
+target. Usually, the information for each piece of the snapshot are the same
+unless an error occurred during the snapshot operations, such as partly
+modification or mount. This option allow to check related issues.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot's name to be queried. If no name is specified, then all the
+snapshots belong to current Lustre filesystem will be listed.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
+.TP
+.B snapshot_mount \fR<-F | --fsname fsname> [-h | --help] <-n | --name ssname>
+ \fR[-r | --rsh remote_shell]
+.br
+Mount the specified snapshot on the servers. Be as read only mode Lustre
+filesystem, if the snapshot is mounted, then it cannot be renamed. It is
+the user's duty to mount client (must as read only mode "-o ro") to the
+snapshot when need.
+NOTE: the snapshot has its own fsname that is different from the original
+filesystem fsname, it can be queried via snapshot_list.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot (to be mounted) name must be specified.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
+.TP
+.B snapshot_umount \fR<-F | --fsname fsname> [-h | --help] <-n | --name ssname>
+ \fR[-r | --rsh remote_shell]
+.br
+Umount the specified snapshot.
+.TP
+ -F, --fsname
+The filesystem name.
+.TP
+ -h, --help
+For help information.
+.TP
+ -n, --name <ssname>
+The snapshot (to be umounted) name must be specified.
+.TP
+ -r, --rsh <remote_shell>
+Specify a shell to communicate with remote targets. The default value is 'ssh'.
+It is the system admin's duty to guarantee that the specified 'remote_shell'
+works well among targets without password authentication.
.SS Debug
.TP
.BI debug_daemon
git://git.whamcloud.com / fs / lustre-release.git / commitdiff