Are Shadow Image and True Copy “full volume copy” or “differential copy”?
Thanks in advance
SI and TC are full independent copies, no snapshots. Both do a full initial copy, using a bitmap at both sides to provide differential updates.
It means (simplified, there are a lot of options and operations):
1) You perform an initial (full copy) from A to B
2) Copy is automatically keep in-sync (different behavior at SI/TC/HUR)
3) You split the copy at T time, mount the B copy and modify it
4) When you resync the copy, tracks that changed since T time at A and tracks that changed since T time at B (the OR union of bitmaps) are copied from A to B
5) Go to step 2 and repeat
Adding my two cents to Pablo Bucich , Shadow image can happen only within the storage box (In-system Replication for testing etc) and TC/TCE/HUR happens outside the box(which will be majorly used for DR solutions)
Retrieving data ...