HP XP RAID Manager Software - Manual (Page 7)

to data in the data pool and P-VOL actually reside in cache memory. Because of this, part of your
system’s cache is reserved for Snapshot when it is enabled.
Figure 1 How V-VOL maintains point-in-time data when pair is split (1)
Figure 2 How V-VOL maintains point-in-time data when pair is split (2)
Figure 3 How V-VOL maintains point-in-time data when pair is split (3)
Data pools
The data pool holds data from the P-VOL that is being replaced.
After a pair is split, the V-VOL maintains pointers to point-in-time data. If updates are written to the
P-VOL, before the block is updated, the data that is being replaced is first copied to the data pool.
The V-VOL pointer to this block is updated to the new address in the data pool.
A data pool is used by all pairs sharing the same P-VOL.
How Snapshot works 7