HP XP7 Storage - Manual (Page 12)

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Initial Copy Priority. You specify the order in which copying is performed on multiple pairs.
This is used if more pairs are being created in the operations than the maximum initial copy
activity setting.
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Round Trip Time. You specify the time limit for data to travel from P-VOL to S-VOL. The value
is used by the storage system to control initial copy pace when update copying is in progress.
These options are available on Remote Web Console. Copy pace is also available using RAID
Manager.
Update copy
Update copy has a higher priority than initial copy. However, if an initial copy is in progress when
updates are sent by the host, the update copy must wait until the initial copy’s copy pace completes.
For example, if the copy pace is 15 tracks, the update copy may wait up to 15 tracks (1 cylinder).
When the host issues an update after the initial copy is complete, the data is written to the P-VOL
and copied to the S-VOL. Subsequent updates are held until the current update is completed in
both volumes. This keeps the pair synchronized.
12 Continuous Access Synchronous Z overview