[clug] a few LVM questions
daniel at rimspace.net
Sun Aug 16 08:28:33 MDT 2009
Andrew <andrew at donehue.net> writes:
> I'm running a few virtual machines on a LVM volume (and I have some space on
> the base partition for snapshots).
> I have been allocating 3GB for a snapshot (and then rsync the vm's to
> another server). I was wondering if there is any way to work out how much
> of this space is actually being used?
In the snapshot? Run lvs as root and it will show you the percentage of space
consumed; it probably supports other figures as well, but I never bothered to
look for them. That one fact has been enough for me.
> I also noticed that when I create the snapshot it blocks all writing for the
> virtual machines when the snapshot is being created (which does create some
> problems from time to time),
Correct. It necessarily blocks writes while it creates the snapshot
mappings. That shouldn't take more than a second or two, though, and the
writes are stopped from hitting disk, not much more, generally.
> googling around said that this wasn't a problem in earlier kernels, but some
> other users have noticed this as well. Anyhow, was wondering if anyone else
> had experienced this?
Nope. Snapshots are as fast as they always were.
✣ Daniel Pittman ✉ daniel at rimspace.net ☎ +61 401 155 707
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