On Thu, 2006-01-12 at 14:32 -0500, Mike Snitzer wrote: > On 1/11/06, Ming Zhang <mingz@xxxxxxxxxxx> wrote: > > On Wed, 2006-01-11 at 20:54 +0000, Alasdair G Kergon wrote: > > > > Efficient, unlikely with the current implemention - hence the need > > > for a rewrite. > > > > > > > > If you have 5 snapshots of the same origin, the current implemention > > > takes 5 copies of the data when you change it. That approach is > > > never going to scale well! And it uses lots of memory. > > > > yes, you are right. is there any new rewrite action proposed or planned? > > My understanding is that much of RedHat's Cluster Snapshot Block > Device (CSNAP) core is a candidate for the dm-snapshot rewrite: > http://sources.redhat.com/cluster/csnap/csnap.ps > > Along with other improvements, performance would be addressed with a > shared exception table (tree) for all snapshots (only one copy of each > exception). When I spoke with Daniel Phillips (author of CSNAP > stuffs) a few months ago he said CSNAP is on the back burner until > others realize just how bad the existing dm-snapshot is. He is > looking/waiting for others who are willing to contribute in moving > CSNAP's snapshot improvements into dm-snapshot++. Unfortunately I'd > only be able to contribute testing at this time... Thanks a lot for this information! Just have a quick glimpse on abstract. Looks interesting. > > Mike -- dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
