From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id oAQE4IOH168861 for ; Fri, 26 Nov 2010 08:04:19 -0600 Received: from mailsrv14.zmi.at (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id BCB9515D9789 for ; Fri, 26 Nov 2010 06:05:54 -0800 (PST) Received: from mailsrv14.zmi.at (mailsrv1.zmi.at [212.69.164.54]) by cuda.sgi.com with ESMTP id ESnBmIjoaMqu87t0 for ; Fri, 26 Nov 2010 06:05:54 -0800 (PST) From: Michael Monnerie Subject: Re: Verify filesystem is aligned to stripes Date: Fri, 26 Nov 2010 15:05:41 +0100 References: <4CED5BFC.8000906@shiftmail.org> <20101126091622.264830fa@galadriel.home> <20101126122218.GH12187@dastard> In-Reply-To: <20101126122218.GH12187@dastard> MIME-Version: 1.0 Message-Id: <201011261505.50658@zmi.at> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============2007558401837647749==" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com Cc: Stan Hoeppner --===============2007558401837647749== Content-Type: multipart/signed; boundary="nextPart1361904.07iAanGdv0"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart1361904.07iAanGdv0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable On Freitag, 26. November 2010 Dave Chinner wrote: > FWIW, for workloads that do random, small IO, XFS works best when you > turn off aligned allocation and just let it spray the IO at the > disks. This works best if you are using RAID 0/1/10. All the numbers > I've been posting are with aligned allocation turned off (i.e. no > sunit/swidth set). That's interesting to read. Why would sunit/swidth be slower then? I'd thought that XFS then would=20 know one stripe is 64k and I have 8 disks so it should try to pack=20 8*64=3D512kb in one junk on disk, and that especially for small files it=20 would write them like that. The man page just says inodes, log are stripe aligned, and file tails=20 >512k extended to full stripes on append. I thought that even the=20 inode/log alignment alone would help a lot. Now what is the advantage on skipping sunit/swidth altogether? And what is the difference when it's on RAID10 to RAID6? I'm always eager to understand performance issues ;-) =2D-=20 mit freundlichen Gr=FCssen, Michael Monnerie, Ing. BSc it-management Internet Services: Prot=E9ger http://proteger.at [gesprochen: Prot-e-schee] Tel: +43 660 / 415 6531 // ****** Radiointerview zum Thema Spam ****** // http://www.it-podcast.at/archiv.html#podcast-100716 //=20 // Haus zu verkaufen: http://zmi.at/langegg/ --nextPart1361904.07iAanGdv0 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (GNU/Linux) iEYEABECAAYFAkzvvr4ACgkQzhSR9xwSCbThiQCffgjuLp/GIWTeA81J7aj5ooGW SSIAoLe1AsOF8pLQVHELm4M541o5YGqv =90Un -----END PGP SIGNATURE----- --nextPart1361904.07iAanGdv0-- --===============2007558401837647749== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs --===============2007558401837647749==--