Snapshot copies that span storage systems or volumes
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SnapDrive for UNIX enables you to take Snapshot copies that reside in multiple storage system volumes on the same or different storage systems.
SnapDrive for UNIX allows you to take Snapshot copies that span across multiple storage system volumes or multiple storage systems. These volumes can reside on the same storage system or different storage systems. Although the
snapdrive snap create command creates a Snapshot copy of all the volumes that comprise the entity you request, SnapDrive for UNIX restores only the entities that you specify in the
snapdrive snap create command.
When you use the
snapdrive snap create command to make a Snapshot copy that spans multiple volumes, you do not need to name the volumes on the command prompt. SnapDrive for UNIX gets this information from the
file_spec argument that you specify.
file_specyou enter requests a disk group, or a file system or host volume that resides on a disk group, SnapDrive for UNIX automatically creates a Snapshot copy that includes all the storage system volumes for the disk group, volume, or file system you specified.
file_specyou enter requests a LUN, SnapDrive for UNIX takes a Snapshot copy of the storage system volume that contains the LUN.
file_specyou enter requests a file system that resides directly on a LUN, SnapDrive for UNIX takes a Snapshot copy of the storage system volume that contains the LUN and file system that you specified.
file_specyou enter requests an NFS directory, SnapDrive for UNIX creates a Snapshot copy of the volume that contains the NFS directory tree.
In addition to using a
file_spec argument that is built on entities from multiple storage systems and storage system volumes, you can also use a combination of
file_spec arguments where each value is based on single storage system or storage system volume. For example, suppose you have a setup where the disk group dg1 spans the storage systems storage system2 and storage system3, dg2 is on storage system2, and dg3 is on storage system3. In this case, any of the following command lines would be correct:
snapdrive snap create -dg dg1 -snapname snapdg1
snapdrive snap create -dg dg2 dg3 -snapname snapdg23
snapdrive snap create -dg dg1 dg2 dg3 -snapname snapdg123
Something to keep in mind when creating Snapshot copies that span storage systems and volumes is that SnapDrive for UNIX creates the Snapshot copy on each storage systems volume using a short name. It does not include the full path name in the name, even if the volumes are on different storage system. This means that if you later rename the Snapshot copy, you must go to each storage system and volume and rename it there as well.