HP 3PAR Operating System Software - Manual (Page 198)

To ensure volume group consistency, Remote Copy maintains all the snapshots for the secondary
asynchronous periodic volume group on the backup system until all of the virtual volumes in that
volume group are synchronized. For more information, see
“Remote Copy Snapshots” (page 203) .
Asynchronous Periodic Mode Volume Groups
For asynchronous periodic mode volume groups:
1.
The initial synchronization (a full synchronization) creates snapshots on the backup system.
2. Until the primary and secondary volume groups are synchronized again, the primary system
accepts I/O, creates snapshots, acknowledges the I/O, and resumes accepting I/O [
Figure 38
(page 198) ]. For more information on this process, see “Volume Group Modes” (page 194) .
Figure 38 Snapshot Creation before Resynchronization (Asynchronous Periodic Mode)
3. When the asynchronous periodic volume groups are synchronized again (either automatically
according to schedule or manually via the syncrcopy command), the system performs either
a full synchronization or a resynchronization.
Full Synchronization
Remote Copy performs a full synchronization if either:
•
The primary volume was never successfully synchronized, or
•
No valid resynchronization snapshot exists (in other words, the resync snapshot has become
stale or otherwise invalid).
When performing a full synchronization ( Figure 39 (page 199) ), Remote Copy:
1. takes a snapshot of all the data in the primary volume
2. transmits the snapshot to the secondary volume
3. completes synchronization
198 Synchronization Types and Limits