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From: Roman Mamedov <rm@romanrm.net>
To: Duncan <1i5t5.duncan@cox.net>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: I need to P. are we almost there yet?
Date: Sun, 4 Jan 2015 02:58:35 +0500	[thread overview]
Message-ID: <20150104025835.02f0d6b8@natsu> (raw)
In-Reply-To: <pan$872b8$2e173aaa$59613c61$c4e30dfd@cox.net>

On Sat, 3 Jan 2015 13:11:57 +0000 (UTC)
Duncan <1i5t5.duncan@cox.net> wrote:

> > What about using btrfs on top of MD raid?
> 
> The problem with that is data integrity.  mdraid doesn't have it.  btrfs 
> does.

Most importantly however, you aren't any worse off with Btrfs on top of MD,
than with Btrfs on a single device, or with Ext4/XFS/JFS/etc on top of MD.

Sure you don't get checksum-based recovery from partial corruption of a RAID,
but you do get other features of Btrfs, such as robust snapshot support,
ability to online-resize up and down, compression, and actually, checksum
verification: even if it won't be able to recover from a corruption, at least
it will warn you of it (and you could recover from backups), while other FSes
will pass through the corrupted data silently.

So until Btrfs multi-device support is feature-complete (and yes that includes
performance-wise), running Btrfs in single-device mode on top of MD RAID is
arguably the most optimal way to use Btrfs in a RAID setup.

(Personally I am running Btrfs on top of 7x2TB MD RAID6, 3x2TB MD RAID5 and
2x2TB MD RAID1).

-- 
With respect,
Roman

  parent reply	other threads:[~2015-01-03 21:58 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-29 18:56 I need to P. are we almost there yet? sys.syphus
2014-12-29 19:00 ` sys.syphus
2014-12-29 19:04   ` Hugo Mills
2014-12-29 20:25     ` sys.syphus
2014-12-29 21:50       ` Hugo Mills
2014-12-29 21:16   ` Chris Murphy
2014-12-30  0:20     ` ashford
     [not found]       ` <CALBWd85UsSih24RhwpmDeMjuMWCKj9dGeuZes5POj6qEFkiz2w@mail.gmail.com>
2014-12-30 17:09         ` Fwd: " Jose Manuel Perez Bethencourt
2014-12-30 21:44       ` Phillip Susi
2014-12-30 23:17         ` ashford
2014-12-31  2:45           ` Phillip Susi
2014-12-31 17:27             ` ashford
2014-12-31 23:38               ` Phillip Susi
2015-01-01  1:26               ` Chris Samuel
2015-01-01 20:12                 ` Roger Binns
2015-01-02  3:47                   ` Duncan
2015-01-02 13:42               ` Austin S Hemmelgarn
2015-01-02 17:45                 ` Brendan Hide
2015-01-02 19:41                   ` Austin S Hemmelgarn
2014-12-29 21:13 ` Chris Murphy
2015-01-03 11:34 ` Bob Marley
2015-01-03 13:11   ` Duncan
2015-01-03 18:53     ` Bob Marley
2015-01-03 19:03       ` sys.syphus
2015-01-03 18:55     ` sys.syphus
2015-01-04  3:22       ` Duncan
2015-01-04  3:54         ` Hugo Mills
2015-01-03 21:58     ` Roman Mamedov [this message]
2015-01-04  3:24       ` Duncan

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