On Mon, Jan 16, 2012 at 02:38:17PM +0000, Joe Thornber wrote: > > There are a couple of documents here: > > https://github.com/jthornber/storage-papers/tree/master/thinp-snapshots-2011 > > I'll be updating the presentation soon for a talk next month. Hi Joe, Thanks for making a pointer to the paper available! I have a question about one of the slides, where you say: "snapshots of external origins". Am I correct in suppose this means you can take a snapshot of something which is currently not a thin-provisioned volume? If so, is this currently implemented? Looking at the documentation in the v3.2's Documentation/device-mapper/thin-provisioning.txt, I don't see a way of doing it: create_snap <dev id> <origin id> Create a new snapshot of another thinly-provisioned device. <dev id> is an arbitrary unique 24-bit identifier chosen by the caller. <origin id> is the identifier of the thinly-provisioned device of which the new device will be a snapshot. Is this a feature which is yet to be implemented? And if so, what's the timeline for implementing it. If this is not a feature to be implemented, can I please put it on the wishlist? I can imagine a lot of ext4 users who would be interested in thin-provisioning, especially if there is discard support such than when we delete a file, we send a discard which causes the thin-provisioned space in the snapshot to be dropped. (This is also apparently not implemented, from what I can tell from the source; do you have an approximate idea of where in the priority list / when it is scheduled to be implemented?) Many thanks, - Ted -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
