xfs
[Top] [All Lists]

Re: A little RAID experiment

To: Linux fs XFS <xfs@xxxxxxxxxxx>
Subject: Re: A little RAID experiment
From: Stefan Ring <stefanrin@xxxxxxxxx>
Date: Wed, 10 Oct 2012 16:57:47 +0200
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=TnsGYy4XHUpmnON6cPga0doaKR1E7Zf2tvDg+3254Zc=; b=UqeCNfStGW/85tVtzWMIYNsc7okPmnPHZC7iYR1iUMuqWQmfMwTRJakyb+QUEzimam +kXoyv+A1rmpIsn3W/vhuq7W2sQP+HSYZeCmfOWqiV3rG3ixtqOEx0k7vVhsCug98IIr A0rJgcY6V1hUmTmoCgk1Q5QaC9N2Hg0wOxyF13jJGM7LEZUR4143V7DlUm/Xbkkp4OID DoAMUGzqiU4x5lJFrlwxN7Vm2KD+eY/Q7GXGjOysANdVsQ9ZQXWUf5A/ueeZvRLhGiXo m4tTkpZGdmmQ6tEpsbvuU0PfVggFNffmfzA4SsSsQEFaw5VZIN7aOCf6fWahzxPEORYD 8RXw==
In-reply-to: <CAAxjCEzh3+doupD=LmgqSbCeYWzn9Ru-vE4T8tOJmoud+28FDQ@xxxxxxxxxxxxxx>
References: <CAAxjCEzh3+doupD=LmgqSbCeYWzn9Ru-vE4T8tOJmoud+28FDQ@xxxxxxxxxxxxxx>
Btw, one of our customers recently aquired new gear with HP SmartArray
Gen8 controllers. Now they are something to get excited about! This is
the kind of write performance I would expect from an expensive server
product. Check this out (this is again my artificial benchmark as well
as random write of 4K blocks):

SmartArray P400, 6 300G disks (10k, SAS) RAID 6, 256M BBWC:

ag4
Read 0b  Written 161.56Mb  Total transferred 161.56Mb  (5.3853Mb/sec)
 1378.63 Requests/sec executed

random write
Read 0b  Written 97.578Mb  Total transferred 97.578Mb  (3.2526Mb/sec)
  832.66 Requests/sec executed

SmartArray Gen8, 8 300G disks (15k, SAS) RAID 5, 2GB FBWC:

ag4
Read 0b  Written 2.4575Gb  Total transferred 2.4575Gb  (83.883Mb/sec)
21474.03 Requests/sec executed

random write
Read 0b  Written 343.86Mb  Total transferred 343.86Mb  (11.462Mb/sec)
 2934.24 Requests/sec executed

So yeah, the disks are a bit faster. But what does that matter when
there is such a huge difference otherwise?

Unfortunately, while composing this text, I noticed that the new one
is configured as RAID 5, and I cannot change it because of HP's
licensing policy. That makes it not a meaningful comparison, although
extrapolation from previous SmartArray controllers would suggest that
the RAID5 and RAID6 performance is comparable.

My subjective impression is still a very good one!

<Prev in Thread] Current Thread [Next in Thread>