My question is about how the cow work when there are multiple snapshots.
Will lvm copy original block to each of the snapshot? Or just copy to one snapshot and redirect other snapshot to the new place of original block?
Why doesn't lvm copy old block to new one which can be written, and the old block could still be referred by snapshots? I think this only need one copy.
I need using lvm snapshot for backuping mongodb once a week. this will create many snapshots. I'm afraid lvm will cost too much while there are many snapshots when writing to an old block.
