From: Stan Hoeppner <stan@hardwarefreak.com>
To: Martin Steigerwald <Martin@lichtvoll.de>
Cc: Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
Eric Sandeen <sandeen@sandeen.net>,
xfs@oss.sgi.com
Subject: Re: xfs_growfs / planned resize / performance impact
Date: Sun, 05 Aug 2012 07:34:58 -0500 [thread overview]
Message-ID: <501E6872.6000503@hardwarefreak.com> (raw)
In-Reply-To: <201208051303.09337.Martin@lichtvoll.de>
On 8/5/2012 6:03 AM, Martin Steigerwald wrote:
> Well the default was 16 AGs for volumes < 2 TiB AFAIR. And it has been
> reduced to 4 for as I remember exactly performance reasons. Too many AGs
> on a single device can incur too much parallelity. Thats at least is what
> I have understood back then.
For striped md/RAID or LVM volumes mkfs.xfs will create 16 AGs by
default because it reads the configuration and finds a striped volume.
The theory here is that more AGs offers better performance in the
average case on a striped volume.
With hardware RAID or a single drive, or any storage configuration for
which mkfs.xfs is unable to query the parameters, mkfs.xfs creates 4 AGs
by default. The 4 AG default has been with us for a very long time. It
was never reduced.
--
Stan
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next prev parent reply other threads:[~2012-08-05 12:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-31 13:56 xfs_growfs / planned resize / performance impact Stefan Priebe - Profihost AG
2012-07-31 17:27 ` Stan Hoeppner
2012-08-03 4:03 ` Eric Sandeen
2012-08-03 6:09 ` Stefan Priebe - Profihost AG
2012-08-03 13:46 ` Eric Sandeen
2012-08-05 11:03 ` Martin Steigerwald
2012-08-05 12:34 ` Stan Hoeppner [this message]
2012-08-05 13:49 ` Martin Steigerwald
2012-08-05 20:26 ` Stan Hoeppner
2012-08-05 15:54 ` Stefan Priebe
2012-08-06 11:42 ` Michael Monnerie
2012-08-04 22:43 ` Dave Chinner
2012-08-05 5:46 ` Stefan Priebe
2012-08-05 11:06 ` Martin Steigerwald
2012-08-05 11:35 ` Andy Bennett
2012-08-05 20:57 ` Dave Chinner
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