HP XP Business Copy Software - Manual (Page 24)

24 ShadowImage for the XP1024/XP128/XP12000/XP10000/SVS 200
NOTE: Use the CSUSPEND and PPRCOPY SUSPEND commands to split SI390 volume pairs. For more
information on using PPRC commands to perform SI390 operations on the
XP1024/XP128/XP12000/XP10000/SVS 200, see ” Using PPRC Commands for ShadowImage ” on
page 76.
Resynchronize Pair Operations (Normal, Quick, Reverse, Quick Restore)
To change the status of pairs from Split to Duplex or from Suspend to Duplex, you must resynchronize the
pairs. ShadowImage performs the following types of resync operations according to the speed and
direction of the resynchronization:
• Normal copy
• Quick resync
• Reverse copy
• Quick restore
The Resynchronize Volume Pair pane (see ” Resynchronizing ShadowImage Pairs ” on page 62) allows you
to resynchronize split and suspended ShadowImage for z/OS pairs. When the resync operation starts, the
pair status changes to resync or resync-r. When the resync is complete, the pair status changes to duplex.
Command View XP or XP Remote Web Console resumes Slz update copy operations after the pair status
changes to duplex. The S-VOL remains fully accessible during a normal or quick resync operation, but is
inaccessible to all hosts during a reverse copy or quick restore operation. This ensures that data on the
S-VOL is identical to data on the T-VOL when the reverse copy or quick restore operation completes.
NOTE: You can use ShadowImage for z/OS to perform normal and quick resync operations on split and
suspended pairs, but you can perform reverse copy operations only on split pairs.
Forward Pairresync Operation
Forward pairresync operation resynchronizes pairs by copying data on S-VOLs to T-VOLs. The following are
the types of forward pairresync operations:
• Normal. The normal resync operation (see Figure 4 ) resynchronizes the T-VOL with the S-VOL. The copy
direction for a normal resync operation is S-VOL to T-VOL. The pair status during a normal resync
operation is resync, and the S-VOL remains accessible to all hosts for both read and write operations
during a normal resync operation. The T-VOL becomes inaccessible to all hosts during a normal resync
operation.
• Quick. The quick resync operation (see Figure 4 ) speeds up the normal resync operation without
copying the S-VOL data to the T-VOL. The S-VOL and the T-VOL are resynchronized when update copy
operations are performed for duplex pairs. The pair status during a quick resync operation is resync,
and the S-VOL remains accessible to all hosts for both read and write operations. The T-VOL becomes
inaccessible to all hosts during a quick resync operation.
Figure 4 Forward pairresync operations