LVM Snapshot Merging for the Linux KernelAug 12, 2008, 12:33 (0 Talkback[s])
[ Thanks to Mr Rough for this link. ]
"While the merging is active, any accesses to the origin device are dicrected the snapshot that is being merged. When the merging finishes, the origin target is seamlessly reloaded and the merging snapshot is dropped. The filesystem can stay mounted during this time."