From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nix Subject: Re: Encrypted software RAID1 with Debian Stretch Date: Fri, 15 Sep 2017 12:35:41 +0100 Message-ID: <87k210p52q.fsf@esperi.org.uk> References: <28c61e8c14f44ec6727b8f3fb3c80c98@riseup.net> <59A92C91.7010508@youngman.org.uk> <87y3pjv6jw.fsf@esperi.org.uk> <3a85ea27-602a-3f5b-3537-d4159a56c2ed@thelounge.net> <87377qvh7t.fsf@esperi.org.uk> <59B95891.9040809@youngman.org.uk> <87r2v9sfkm.fsf@esperi.org.uk> <59BA6FAF.9020501@youngman.org.uk> <878thhsa0w.fsf@esperi.org.uk> <20170914183932.001ffe25@natsu> <87wp51qq60.fsf@esperi.org.uk> <20170914212206.272b1289@natsu> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20170914212206.272b1289@natsu> (Roman Mamedov's message of "Thu, 14 Sep 2017 21:22:06 +0500") Sender: linux-raid-owner@vger.kernel.org To: Roman Mamedov Cc: Wols Lists , linux-raid List-Id: linux-raid.ids On 14 Sep 2017, Roman Mamedov said: > On Thu, 14 Sep 2017 16:02:31 +0100 > Nix wrote: > >> I would never consider snapshots on the same filesystem to be a backup >> of anything, except possibly as a defence against 'oh whoops I rm'ed the >> wrong tree'. > > No one proposed that. Oh I thought that was what people were proposing as the compelling btrfs advantage. > The scenario is that the backup server would have its > rsync destination dir (from multiple other systems) periodically snapshotted, > providing a historic view of what it contained 1-2-3 months ago. Just like > "bup" does in userspace, I guess? -- or like rdiff-backup did, which I used > before. But now we have that directly in filesystem, no need to cling to > userspace crutches anymore. I'm fairly sure that can't deduplicate anywhere near as effectively. No dedup within files; no dedup across trees (very important if you have duplicated data on multipl systems you are backing up); no dedup anywhere except in immediate history. That's all rdiff-backup could do, but the state of the art is better now. -- NULL && (void)