From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 9028329DF8 for ; Tue, 4 Jun 2013 17:59:39 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay1.corp.sgi.com (Postfix) with ESMTP id 7D1558F8035 for ; Tue, 4 Jun 2013 15:59:39 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [150.101.137.143]) by cuda.sgi.com with ESMTP id DXv6LPKcFWJZia8s for ; Tue, 04 Jun 2013 15:59:37 -0700 (PDT) Date: Wed, 5 Jun 2013 08:59:35 +1000 From: Dave Chinner Subject: Re: Debunking myths about metadata CRC overhead Message-ID: <20130604225935.GM29466@dastard> References: <20130603074452.GZ29466@dastard> <20130603111011.461d10b5@galadriel.home> <20130604025307.GB29466@dastard> <1370371109.3898.10.camel@chandra-dt.ibm.com> <20130604220849.GK29466@dastard> <1370385616.22504.7.camel@chandra-dt.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1370385616.22504.7.camel@chandra-dt.ibm.com> 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 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Chandra Seetharaman Cc: xfs@oss.sgi.com On Tue, Jun 04, 2013 at 05:40:16PM -0500, Chandra Seetharaman wrote: > On Wed, 2013-06-05 at 08:08 +1000, Dave Chinner wrote: > > On Tue, Jun 04, 2013 at 01:38:29PM -0500, Chandra Seetharaman wrote: > > > On Tue, 2013-06-04 at 12:53 +1000, Dave Chinner wrote: > > > > On Mon, Jun 03, 2013 at 11:10:11AM +0200, Emmanuel Florac wrote: > > > > > Le Mon, 3 Jun 2013 17:44:52 +1000 vous =E9criviez: > > > > > = > > > > > > There has been some assertions made recently that metadata CRCs= have > > > > > > too much overhead to always be enabled. So I'll run some quick > > > > > > benchmarks to demonstrate the "too much overhead" assertions are > > > > > > completely unfounded. > > > > > = > > > > > Just a quick question: what is the minimal kernel version and xfs= progs > > > > > version needed to run xfs with metadata CRC? I'd happily test it = on > > > > > real hardware, I have a couple of storage servers in test in the = 40 to > > > > > 108 TB range. > > > > = > > > > If the maintainers merge all the patches I send for the 3.10-rc > > > > series, then the 3.10 release should be stable enough to use for > > > > testing with data you don't care if you lose. > > > > = > > > > As for the userspace code - that is still just a patchset. I haven't > > > > had any feedback from the maintainers about it in the past month, so > > > > I've got no idea what they are doing with it. I'll post out a new > > > > version in the next couple of days - it's 50-odd patches by now, so > > > > it'd be nice to have it in the xfsprogs git tree so people could > > > > just pull it and build it for testing purposes by the time that 3.10 > > > > releases.... > > > = > > > Dave, > > > = > > > I was of the impression that the user space changes will be released > > > sometime later (i.e when CRC comes out of experimental). If we make t= he > > > user space changes to create V5 filesystem now, it will be an annoyan= ce > > > for people that created V5 super blocks without my changes (getting r= id > > > of OQUOTA.* flags). = > > = > > People still need access to the code to test it. I'm not talking > > about an official release here at all, just getting it committed to > > the git tree to make it easy for people to get the code and for > > developers to build on top of it and fix bugs. > > = > = > Oh, I see. It is clear now. > = > Also, is there a git tree where I can pull your xfsprogs changes from ? > I tried to apply xfsprogs-kern-sync-patchset-v2.tar.gz on top of > xfsprogs git tree, it seems to have some problems. > = > Or is there a later version ? I'm cleaning up my current tree right now. I'll post it out as soon as it is ready to go. Hopefully Ben can get that into a branch in the xfsprogs git tree and you can pull from there. Cheers, Dave. -- = Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs