Operating System Software Owner manual

29 Synchronization Types and Limits
See:For more information on:
“Types of Synchronization” (page 197)The two types of synchronization Remote Copy performs
“Limits on Volumes that Concurrently Synchronize”
(page 197)
The number of virtual volumes that Remote Copy
synchronizes at the same time
“Asynchronous Periodic Mode Volume Groups” (page 198)How Remote Copy synchronizes asynchronous periodic
mode volume groups
“Setting Up Resynchronization for Asynchronous Periodic
Mode” (page 201)
Considerations for resynchronizing asynchronous periodic
volume groups
“Synchronous Mode Volume Groups” (page 201)How Remote Copy synchronizes synchronous mode volume
groups
Additional Information:
• “Volume Groups” (page 190)
• “Volume Group Modes” (page 194)
Types of Synchronization
Remote Copy performs one of two types of synchronization on volume groups:
FunctionalityType of Synchronization
Remote Copy copies the entire primary volume.full synchronization
Remote Copy copies only the data that has changed since
the previous synchronization.
resynchronization
• When you create a new volume group, the initial synchronization of data is always a full
synchronization, regardless of mode (asynchronous periodic or synchronous).
• Synchronizations are done individually for each volume.
• Depending on the volume group mode, Remote Copy performs different types of
synchronizations at different times.
Limits on Volumes that Concurrently Synchronize
To limit the impact of Remote Copy on the performance of the HP 3PAR Storage System, Remote
Copy limits the number of virtual volumes that can synchronize at the same time to 20 volumes.
This limit:
• is not user-configurable
• applies to the initial synchronization
• applies to resynchronizations, regardless of mode (synchronous or asynchronous periodic)
For more information on volume group modes, see “Volume Group Modes” (page 194).
For example, if Remote Copy is in the process of resynchronizing an asynchronous periodic mode
volume group that contains 30 virtual volumes, you might notice that some of the first 20 volumes
complete synchronization before some of the last 10 volumes start synchronizing.
To view resynchronizations, monitor the SyncStatus column of the showrcopy command output.
For details about the showrcopy command and an example of showrcopy command output,
see “The Remote Copy Commands” (page 224).
Types of Synchronization 197