[linux-lvm] Snapshot behavior on classic LVM vs ThinLVM
Stuart D. Gathman
stuart at gathman.org
Tue Apr 18 14:32:34 UTC 2017
On Tue, 18 Apr 2017, Gionatan Danti wrote:
> Any thoughts on the original question? For snapshot with relatively big CoW
> table, from a stability standpoint, how do you feel about classical vs
> thin-pool snapshot?
Classic snapshots are rock solid. There is no risk to the origin
volume. If the snapshot CoW fills up, all reads and all writes to the
*snapshot* return IOError. The origin is unaffected.
If a classic snapshot exists across a reboot, then the entire CoW table
(but not the data chunks) must be loaded into memory when the snapshot
(or origin) is activated. This can greatly delay boot for a large CoW.
For the common purpose of temporary snapsnots for consistent backups,
this is not an issue.
Stuart D. Gathman <stuart at gathman.org>
"Confutatis maledictis, flamis acribus addictis" - background song for
a Microsoft sponsored "Where do you want to go from here?" commercial.
More information about the linux-lvm