[linux-lvm] Server hangs when writing to LVM volume due to LVM Snapshots

[Dan Kegel]

On Mon, Jun 16, 2008 at 2:18 PM, Veselin Kantsev
<veselin at campbell-lange.net> wrote:
> I think I've misunderstood the concept of snapshots.

No, only how lvm works under the hood.

> So If I have 7 snapshots of the same volume (created at different times)
> and a file is changed, would the change affect all 7 snapshots or
> just the latest one created?

If the file had not changed since the beginning of time,
then when you change it, each block needs to be
written to each snapshot because of the way COW
is implemented in LVM snapshots.

> If the former, then I imagine changing a 1GB+ file, in my
> situation will result in an unpleasant experience with the LVM snapshots.

Correct.  That's why people have been asking for that common
snapshot store for a long time.  Zumastor is more or less a
preview of this long-sought lvm feature.
- Dan