Creating snapshot xp pairs, Storing snapshot data, Restoring snapshot xp pairs – HP StorageWorks XP Remote Web Console Software User Manual
Page 16
16
Snapshot XP
A V-VOL’s definition cannot be released if the V-VOL is being used as a Snapshot XP pair’s S-VOL. To
release the definition, delete the Snapshot XP pair using the V-VOL.
NOTE:
Servers (including RAID Manager) show the V-VOLs with emulation type 0 (for example,
OPEN-0V). When you create a Snapshot XP pair, specify the volume with emulation type 0, such as
OPEN-0V, as the S-VOL.
To delete a V-VOL, use the V-VOL pane in Command View XP or XP Remote Web Console. For more
information, see ”
Creating or deleting virtual volumes
Creating Snapshot XP pairs
A Snapshot XP pair uses a V-VOL as its S-VOL. Therefore, you must create a V-VOL before creating a
Snapshot XP pair. In Snapshot XP, you can specify up to 64 S-VOLs for a P-VOL.
To create Snapshot XP pairs, use a RAID Manager command. For more information, see ”
CAUTION:
When creating Snapshot XP pairs, you decide which pool the pairs use. If you create two or
more Snapshot XP pairs that share the same P-VOL, you must specify the same pool for these pairs. For
example, if you specify three S-VOLs for one P-VOL, you must specify the same pool for these three pairs.
NOTE:
When deleting a Snapshot XP pair, the volumes’ status becomes SMPL(PD). You cannot create
pairs using SMPL(PD) volumes. If the volumes are in SMPL(PD) status, wait for a while and issue the
command to create pairs after the volumes’ status changes to SMPL.
Use the Business Copy XP main pane to see the volume’s status. Using RAID Manager, you can check the
volume status with the
pairdisplay
command, but you cannot distinguish between SMPL and SMPL(PD)
volumes. To distinguish between SMPL and SMPL(PD) volumes using RAID Manager, issue the
inqraid
command as well. The
inqraid
command shows whether Snapshot XP is using the volume. As a result of
the
inqraid
command, if Snapshot XP is not using the volume, the volume status is SMPL. If Snapshot XP
is using the volume, the volume status is SMPL(PD).
Storing snapshot data
Snapshot data is a replica of data in a Snapshot XP pair’s P-VOL, and is stored in a pool. When the P-VOL
is updated, updated data is copied to the pool as snapshot data before the P-VOL is updated. This process
is called storing snapshot data.
If you issue a command to a Snapshot XP pair to store snapshot data, the snapshot data is stored in the
pool when a host issues a write request to the Snapshot XP pair’s P-VOL.
To store snapshot data in a pool, use a RAID Manager command. For more information, see ”
Restoring Snapshot XP pairs
Snapshot XP can restore a P-VOL’s contents to the state when the snapshot data was stored in the pool by
writing the snapshot data back to the P-VOL. Writing the snapshot data to the P-VOL is called restoration of
a Snapshot XP pair.
NOTE:
If you restore the pair when data is written in the S-VOL instead of the snapshot data, data in the
S-VOL is written back to the P-VOL.
If there are problems with the P-VOL data during a failure, you can restore the P-VOL to the normal state
when the snapshot data was stored by executing restoration.