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From: Aryeh Gregor <Simetrical+list@gmail.com>
To: David Rees <drees76@gmail.com>
Cc: Wil Reichert <wil.reichert@gmail.com>,
	linux raid <linux-raid@vger.kernel.org>
Subject: Re: SSD & mechanical disc in RAID 1
Date: Tue, 2 Feb 2010 09:07:31 -0500	[thread overview]
Message-ID: <7c2a12e21002020607j38d35a1bq85d37221b922da0f@mail.gmail.com> (raw)
In-Reply-To: <72dbd3151002011310g57fa9b66j2798aa0acde199b2@mail.gmail.com>

On Mon, Feb 1, 2010 at 4:10 PM, David Rees <drees76@gmail.com> wrote:
> I suspect that if you used write-behind with a write-intent bitmap
> stored only on the SSD, you'd get some of that performance back, but
> potentially lose a bit of reliability.

You'd only lose data here if the SSD died and the machine crashed *at
the same time*, right?  Doesn't seem like a big deal to me -- if the
events are even a minute or two apart, you'd be fine (right?).  By
contrast, if I understand correctly, you can get data corruption in
RAID5 if you lose a disk and then the machine crashes *any* time
before a new disk is resynced.

      reply	other threads:[~2010-02-02 14:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-09 17:53 SSD & mechanical disc in RAID 1 Wil Reichert
2010-01-09 19:23 ` Keld Jørn Simonsen
2010-01-22 16:37   ` Goswin von Brederlow
2010-01-31 20:21     ` Aryeh Gregor
2010-02-01 20:56       ` Wil Reichert
2010-02-01 20:06     ` Bill Davidsen
2010-02-01 21:10 ` David Rees
2010-02-02 14:07   ` Aryeh Gregor [this message]

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