Prerequisite patches (Exception Store API Changes - group 1): http://patchwork.kernel.org/bundle/jbrassow/Exception%20Store%20API%20group1/ This group of patches can be found at: http://patchwork.kernel.org/bundle/jbrassow/Exception%20Store%20API%20group2/ These patches form an exception store API that gives device-mapper snapshots the ability to use different COW device implementations. The current set includes 'persistent/P' and 'transient/N'. Future implementations include 'shared' and 'cluster-aware'. The 'shared' exception store implementation is included (patch 30). It works as far as 'read-only' snapshots are concerned. IOW, you can take snapshots, read and write from the origin, and read from the snapshot... but you can't write to the snapshots yet. Instructions for using snapshots with the shared exception store can be found in patch 30. brassow -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel