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From: Emmanuel Florac <eflorac@intellique.com>
To: Dave Hall <kdhall@binghamton.edu>
Cc: stan@hardwarefreak.com, "xfs@oss.sgi.com" <xfs@oss.sgi.com>
Subject: Re: XFS/LVM/Multipath on a single RAID volume
Date: Mon, 23 Feb 2015 12:18:12 +0100	[thread overview]
Message-ID: <20150223121812.5077ff07@harpe.intellique.com> (raw)
In-Reply-To: <54EA67B7.30805@binghamton.edu>

Le Sun, 22 Feb 2015 18:35:19 -0500
Dave Hall <kdhall@binghamton.edu> écrivait:

> So since I have a fresh array that's not in production yet I was
> hoping to get some pointers on how to configure it to maximize XFS 
> performance.  In particular, I've seen a suggestion that a
> multipathed array should be sliced up into logical drives and pasted
> back together with LVM.  Wondering also about putting the journal in
> a separate logical drive on the same array.

What's the hardware configuration like? before multipathing, you need
to know if your RAID controller and disks can actually saturate your
link. Generally SAS-attached enclosures are driven through a 4 way
SFF-8088 cable, with a bandwidth of 4x 6Gbps (maximum throughput per
link: 3 GB/s) or 4 x 12 Gbps (max thruput: 6 GB/s).

> I am able to set up a 2-way multipath right now, and I might be able
> to justify adding a second controller to the array to get a 4-way
> multipath going.

A multipath can double the throughput, provided that you have enough
drives: you'll need about 24 7k RPM drives to saturate _one_ 4x6Gbps
SAS link. If you have only 12 drives, dual attachment probably won't
yield much.

> Even if the LVM approach is the wrong one, I clearly have a rare
> chance to set this array up the right way.  Please let me know if you
> have any suggestions.

In my experience, software RAID-0 with md gives slightly better
performance than LVM, though not much.


-- 
------------------------------------------------------------------------
Emmanuel Florac     |   Direction technique
                    |   Intellique
                    |	<eflorac@intellique.com>
                    |   +33 1 78 94 84 02
------------------------------------------------------------------------

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  reply	other threads:[~2015-02-23 11:18 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-13 18:11 xfs_fsr, sunit, and swidth Dave Hall
2013-03-13 23:57 ` Dave Chinner
2013-03-14  0:03 ` Stan Hoeppner
     [not found]   ` <514153ED.3000405@binghamton.edu>
2013-03-14 12:26     ` Stan Hoeppner
2013-03-14 12:55       ` Stan Hoeppner
2013-03-14 14:59         ` Dave Hall
2013-03-14 18:07           ` Stefan Ring
2013-03-15  5:14           ` Stan Hoeppner
2013-03-15 11:45             ` Dave Chinner
2013-03-16  4:47               ` Stan Hoeppner
2013-03-16  7:21                 ` Dave Chinner
2013-03-16 11:45                   ` Stan Hoeppner
2013-03-25 17:00                   ` Dave Hall
2013-03-27 21:16                     ` Stan Hoeppner
2013-03-29 19:59                       ` Dave Hall
2013-03-31  1:22                         ` Dave Chinner
2013-04-02 10:34                           ` Hans-Peter Jansen
2013-04-03 14:25                           ` Dave Hall
2013-04-12 17:25                             ` Dave Hall
2013-04-13  0:45                               ` Dave Chinner
2013-04-13  0:51                               ` Stan Hoeppner
2013-04-15 20:35                                 ` Dave Hall
2013-04-16  1:45                                   ` Stan Hoeppner
2013-04-16 16:18                                   ` Dave Chinner
2015-02-22 23:35                                     ` XFS/LVM/Multipath on a single RAID volume Dave Hall
2015-02-23 11:18                                       ` Emmanuel Florac [this message]
2015-02-24 22:04                                         ` Dave Hall
2015-02-24 22:33                                           ` Dave Chinner
     [not found]                                             ` <54ED01BC.6080302@binghamton.edu>
2015-02-24 23:33                                               ` Dave Chinner
2015-02-25 11:49                                             ` Emmanuel Florac
2015-02-25 11:21                                           ` Emmanuel Florac
2013-03-28  1:38                     ` xfs_fsr, sunit, and swidth Dave Chinner

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