From: Linda Walsh <lvm@tlinx.org>
To: LVM general discussion and development <linux-lvm@redhat.com>
Subject: [linux-lvm] access or interface to list of blocks that have changed via C.O.W.?
Date: Thu, 27 Sep 2012 19:51:03 -0700 [thread overview]
Message-ID: <50651097.2060200@tlinx.org> (raw)
I'm trying to use snapshots that are active for a day or so to grab
differences between successive days for allowing me to display previous
versions of files over a month or so...
They aren't a replacement for my daily towero'hanoi-backups, but
they are a great deal easier to use.
The chink in my plan is the time it is taking to do a diff -- not really
a fatal chink but annoying. It takes anywhere from 80-100 minutes for
rsync to sum up the changes and copy them to a third volume each day.
I figured well sheesh, the lvm should already know what sectors are
different. If I could combine that info against a inode+blockmap, I might
get that diff computation down to under 10 minutes maybe under 5.
The contents of the files that are computed as differences by rsync usually
take a minute or less to actually copy into final volume -- anywhere between
800Mb - 2.5GB out of a 1TB volume. So I I could shortcut that diff
process,
might make it practical to do more than one snapshot a day;...
Is there some interface for getting at that information or would it have
to be written from scratch?
Thnks...
Linda
next reply other threads:[~2012-09-28 2:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-28 2:51 Linda Walsh [this message]
[not found] <mailman.18903.1349274978.3548.linux-lvm@redhat.com>
2012-10-03 15:42 ` [linux-lvm] access or interface to list of blocks that have, changed via C.O.W.? Mark Woodward
2012-10-04 2:52 ` Linda Walsh
2012-10-04 3:41 ` Mark Woodward
2012-10-04 5:05 ` Linda Walsh
2012-10-04 10:17 ` Mark Woodward
2012-10-04 14:44 ` Bryn M. Reeves
2012-10-04 15:02 ` Mark Woodward
2012-10-04 22:00 ` Stuart D Gathman
2012-10-05 9:39 ` Bryn M. Reeves
2012-10-05 9:26 ` Bryn M. Reeves
2012-10-05 11:21 ` Mark Woodward
2012-10-16 12:15 ` Mark Woodward
2012-10-17 10:20 ` Lars Ellenberg
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