HP StorageWorks XP Remote Web Console Software - Manual (Page 15)

Creating XP Snapshot pairs
A XP Snapshot pair uses a V-VOL as its S-VOL. Therefore, you must create a V-VOL before creating
a XP Snapshot pair. In XP Snapshot, you can specify up to 64 S-VOLs for a P-VOL.
To create XP Snapshot pairs, use a XP RAID Manager command. For more information, see
“
Creating Snapshot XP pairs ” on page 64.
CAUTION:
When creating XP Snapshot pairs, you decide which pool the pairs use. If you create two or more
XP Snapshot 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 XP Snapshot 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 XP Business Copy main pane to see the volume's status. Using XP 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 XP RAID Manager,
issue the
inqraid command as well. The inqraid command shows whether XP Snapshot is using the
volume. If XP Snapshot is not using the volume, the volume status is SMPL. If XP Snapshot is using the
volume, the volume status is SMPL(PD).
Storing snapshot data
Snapshot data is a replica of data in a XP Snapshot 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 XP Snapshot pair to store snapshot data, the snapshot data is stored in
the pool when a host issues a write request to the XP Snapshot pair's P-VOL.
To store snapshot data in a pool, use a XP RAID Manager command. For more information, see
“
Storing snapshot data ” on page 64.
Restoring XP Snapshot pairs
XP Snapshot 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 XP Snapshot 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.
XP Snapshot User Guide 15