Multiple concurrent snapshots - what are the implications?
Hi all,
I am trying to wrap my head around the implications of utilizing multiple concurrent snapshots of the same LV.
What I seem not to get from my searches, is how it really works, if you do the follwoing:
- create a snpshot from a LV
- modify data on the LV (which is of course modified in the snapshot, due to COW)
- create another snapshot from the same LV
- modify data on the LV (deltas will be written on both snapshots)
If I now delete the 2nd snapshot, there's really nothing to do, since the deltas in snapshot2 are already present in snapshot1, but what if I delete the first snapshot before the second? Will the deltas then be carried over to the 2nd snapshot and the other ones, if ther're even more of them present?
Well… seems that I misunderstood the concept of COW… , but I took a piece of paper and a pencil and worked it out.
So , since the snapshots are a view on the original LV, plus the list of blocks that have been copied before they have been altered, all snapshots are indeed completely seperate form one another.