mmpsnap command
Creates or deletes identical snapshots on the cache and home clusters, or shows the status of snapshots that have been queued up on the gateway nodes.
Synopsis
mmpsnap Device create -j FilesetName [[--comment Comment] {[--uid ClusterUID] | --rpo}] [--wait]
or
mmpsnap Device delete -s SnapshotName -j FilesetName
or
mmpsnap Device status -j FilesetName
Availability
Available with IBM Spectrum Scale™ Standard Edition or higher. Available on AIX® and Linux.
Description
The mmpsnap command creates or deletes identical snapshots on the cache and home clusters, or shows the status of snapshots that have been queued up on the gateway nodes. You can use this command only in a Single writer (SW) cache. You cannot use for Read only (RO), Independent writer (IW), or Local updates (LU) caches. Peer snapshots are not allowed on a Single writer (SW) cache that uses the NSD protocol for communicating with home.
Parameters
- Device
- Specifies the device name of the file system.
- create
- Creates a fileset level snapshot in cache and a snapshot with the same name at home. The snapshot at home could be fileset level or file system level, depending on whether the exported path is an independent fileset or file system.
- -j FilesetName
- Specifies the name of the fileset.
- --comment Comment
- Optional; specifies user-defined text to be prepended to the snapshot name (thereby customizing
the name of the snapshot).Note: You must use alphanumeric characters when you customize the snapshot name.
- --uid ClusterUID
- Optional; specifies a unique identifier for the cache site. If not specified, this defaults to the GPFS™ cluster ID.
- --rpo
- Optional; specifies that user recovery point objective (RPO) snapshots are to be created for a primary fileset. This option cannot be specified with the --uid option.
- --wait
- Optional; makes the creation of cache and home snapshots a synchronous process. When specified, mmpsnap does not return until the snapshot is created on the home cluster. When not specified, mmpsnap is asynchronous and returns immediately rather than waiting for the snapshot to be created at home.
- delete
- Deletes the local and remote copies of the specified snapshot; AFM automatically figures out the remote device and fileset.
- -s SnapshotName
- Specifies the name of the snapshot to be deleted. A snapshot name
is constructed as follows:
Where timestamp has the form YY-MM-DD-HH-MM-SS.{commentString}-psnap-{clusterId}-{fsUID}-{fsetID}-{timestamp}
In the following example, a comment string was not provided:psnap-14133737607146558608-C0A8AA04:4EDD34DF-1-11-12-05-14-32-10
- status
- Shows the status of snapshots that have been queued up on the
gateway nodes. The status includes the following pieces of information:
- Last successful snapshot (obtained through mmlsfileset –-afm)
- Status of the current snapshot process.
Exit status
- 0
- Successful completion.
- nonzero
- A failure has occurred.
Security
You must have root authority to run the mmpsnap command.
The node on which the command is issued must be able to execute remote shell commands on any other node in the cluster without the use of a password and without producing any extraneous messages. For more information, see Requirements for administering a GPFS file system.
Examples
- To create a fileset level snapshot in cache of a single-writer fileset called
sw in file system fs1 issue this
command:
The system displays output similar to the following:mmpsnap fs1 create -j sw
Writing dirty data to disk. Quiescing all file system operations. Writing dirty data to disk again. Snapshot psnap-13882361812785649740-C0A80E85:4F44B305-59-12-03-01-02-27-28 created with id 8. Snapshot psnap-13882361812785649740-C0A80E85:4F44B305-59-12-03-01-02-27-28 created at the satellite. Core snapshot has been queued.
- To display the snapshot issue this command:
The system displays output similar to the following:mmlssnapshot fs1 -j sw
Snapshots in file system fs1: Directory SnapId Status Created Fileset psnap-13882361812785649740-C0A80E85:4F44B305-59-12-03-01-02-27-28 8 Valid Thu Mar 1 02:27:29 2012 sw
- To show that the snapshot is also created at home, issue this
command:
The system displays output similar to the following:mmlssnapshot fs1
Snapshots in file system fs1: Directory SnapId Status Created Fileset psnap-13882361812785649740-C0A80E85:4F44B305-59-12-03-01-02-27-28 8 Valid Thu Mar 1 02:23:16 2012
See also
Location
/usr/lpp/mmfs/bin