On Mon, Mar 14, 2011 at 1:53 PM, Chunqiang Tang <ct...@us.ibm.com> wrote: > Therefore, during normal execution of a > VM, images with snapshots are as fast as images without snapshot.
Hang on, an image with a snapshot still needs to do copy-on-write, just like backing files. The cost of copy-on-write is reading data from the backing file, whereas a non-CoW write doesn't need to do that. So no, snapshots are not free during normal execution. Stefan
