+++ This bug was initially created as a clone of Bug #494007 +++ Description of problem: Jonathan Brassow forwarded a note from the lvm-development mailing list with a clear explanation of determining snapshot size. It was written by Bryn Reeves. He recommends I add this to the LVM document. ------------------------ The size of the snapshot governs the amount of space set aside for storing the changes to the origin volume. E.g. if you made a snapshot and then completely overwrote the origin the snapshot would have to be at least as big as the origin volume to hold the changes. You need to dimension a snapshot according to the expected level of change. So for example a short-lived snapshot of a read-mostly volume, e.g. /usr, would need less space than a long-lived snapshot of a volume that sees a greater number of writes such as /home. Snapshots can be grown after they have been created but you need to make sure they don't fill up. If this happens the snapshot will become invalid (since it can no longer faithfully track changes on the origin volume). Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info: --- Additional comment from slevine on 2009-04-03 13:21:17 EDT --- I am adding this information to the RHEL 4 and RHEL 5 versions of the LVM document. This will be in the RHEL 4.8 and the RHEL 5.4 releases (unless we have a major reason to update the online documents on the public web site earlier).
With the release of 4.8 documents, I am closing this bug.