From: Martin Steigerwald <Martin@lichtvoll.de>
To: stan@hardwarefreak.com
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, 5 Aug 2012 15:49:22 +0200 [thread overview]
Message-ID: <201208051549.22830.Martin@lichtvoll.de> (raw)
In-Reply-To: <501E6872.6000503@hardwarefreak.com>
Am Sonntag, 5. August 2012 schrieb Stan Hoeppner:
> 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.
That does not match my memory, but I´d have to look it up. Maybe next
week.
I am pretty sure mkfs.xfs on a single partition on a single harddisk upto
2 TiB used 16 AGs for quite some time and now uses 4 AGs since quite some
time already. I think I have noted the exact xfsprogs version where it was
changed in my training slides.
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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next prev parent reply other threads:[~2012-08-05 13:49 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
2012-08-05 13:49 ` Martin Steigerwald [this message]
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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