On 10/9/06, Vijai Babu Madhavan <MVijai@xxxxxxxxxx> wrote:
Quick summary ========= Various approaches that are being considered/prototyped to solve the scalability problem with DM snapshots are described here. Currently, I like the 2.d approach (using a single cow device for all snapshots of an origin, with a combination of exception stores). If you don't want to read about other approaches, jump there directly. I would like to know about other ways to solve this problem, and comments about these approaches.
A shared exception store was included as part of the cluster snapshot prototype that Daniel Phillips worked on some time ago: http://sources.redhat.com/cluster/csnap/ See section "1.3 Multiple Snapshots" and "5 Server Implementation details" in csnap.ps. And csnap.c in the csnap.0.0.1.tgz This code is quite cluster oriented but it does provide a good amount of detail on how one might implement a shared exception store. I kernel-based solution could come later... It would be _very_ nice to improve the current dm-snapshot with shared exceptions; I for one am eager to see continued discussion/implementation of this. Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
