From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q75DnPH2217390 for ; Sun, 5 Aug 2012 08:49:25 -0500 Received: from mail.lichtvoll.de (mondschein.lichtvoll.de [194.150.191.11]) by cuda.sgi.com with ESMTP id 1HsLd443iQo2QHWu for ; Sun, 05 Aug 2012 06:49:23 -0700 (PDT) From: Martin Steigerwald Subject: Re: xfs_growfs / planned resize / performance impact Date: Sun, 5 Aug 2012 15:49:22 +0200 References: <5017E426.2040709@profihost.ag> <201208051303.09337.Martin@lichtvoll.de> <501E6872.6000503@hardwarefreak.com> (sfid-20120805_153826_573731_00E594B5) In-Reply-To: <501E6872.6000503@hardwarefreak.com> MIME-Version: 1.0 Message-Id: <201208051549.22830.Martin@lichtvoll.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: stan@hardwarefreak.com Cc: Stefan Priebe - Profihost AG , Eric Sandeen , xfs@oss.sgi.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=B4d 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 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs