[dm-devel] Recommendations for cascaded snapshots
Alasdair G Kergon
agk at redhat.com
Sun Oct 1 21:09:21 UTC 2006
On Sun, Oct 01, 2006 at 03:12:01PM -0400, Kyle Moffett wrote:
> Another quickie question: How can I measure the current %use of a
> given snapshot device?
lvs -o snap_percent vgname/lvname
(see man page for formatting options to control output units & suppress
headings etc.)
> My first "solution" was to use stacked snapshots such that the
See the list archives for the thread last week.
I'll review the concept & initial code later this week.
[see LVM2/lib/report/columns.h in the source tree for the definitive
list of fields; we should probably fix the tools to display the
list that got compiled in.]
> First of all, it doesn't seem
> possible to merge two snapshots together
Mark has code to do this for read-only origins (originally implemented in
userspace).
> but I couldn't determine how stable it was or whether
> or not it applied to recent kernels.
I'm part-way through integrating it.
Once the snapshot concurrent read/write bug fix is finally sorted out, it
shouldn't take long.
Alasdair
--
agk at redhat.com
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