From: David Madden <dhm@mersenne.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: OK to take hourly snapshots, then cull older ones?
Date: Mon, 14 Oct 2013 22:05:21 -0700 [thread overview]
Message-ID: <525CCD11.3030203@mersenne.com> (raw)
In-Reply-To: <20131015105306.6a74ec5c@natsu>
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On 14-Oct-2013 21:53 , Roman Mamedov wrote:
> Sure, that's one of the more awesome uses of btrfs.
>
> But keep in mind that old snapshots on the same FS are not to be
> used instead of a proper backup to external media/servers. If a
> block happened not to change for a year, and it gets damaged on
> disk, it will become damaged in all the snapshots all the way back
> to a year ago, and you lose that data.
I haven't looked at the wiki carefully enough to understand this, but
could one reasonably back up the snapshots of one BTRFS filesystem to
an independent BTRFS filesystem, in a more efficient way than just
dump/restore or cpio or something?
It sounds like you could rely on on-the-fly deduping to save space on
the backup filesystem, but you'd still be reading the whole source
snapshot tree and sending it to be deduped/written. Seems like you
could improve things by just pulling the changed blocks from the
snapshot to the previous snapshot, which would (I guess) be the only
blocks actually _in_ the snapshot.
I guess what would really help is a "Best Practices Guide for BTRFS
Snapshotting and Backup." Does anything like that exist?
Thanks,
- --
Mersenne Law LLC · www.mersenne.com · +1-503-679-1671
- - Small Business, Startup and Intellectual Property Law -
1500 SW First Ave. · Suite 1170 · Portland, Oregon 97201
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next prev parent reply other threads:[~2013-10-15 5:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 4:05 OK to take hourly snapshots, then cull older ones? David Madden
2013-10-15 4:43 ` Marc MERLIN
2013-10-15 4:47 ` Duncan
2013-10-15 4:53 ` Roman Mamedov
2013-10-15 5:05 ` David Madden [this message]
2013-10-15 5:14 ` Avi Miller
2013-11-03 11:50 ` Matthias G. Eckermann
2013-11-05 2:51 ` Marc MERLIN
2013-11-06 0:08 ` Matthias G. Eckermann
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