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 o6KDJhok021914 for ; Tue, 20 Jul 2010 08:19:44 -0500 Received: from mailsrv14.zmi.at (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 867651B8B580 for ; Tue, 20 Jul 2010 06:22:41 -0700 (PDT) Received: from mailsrv14.zmi.at (mailsrv1.zmi.at [212.69.164.54]) by cuda.sgi.com with ESMTP id z67Zd3aNuIFHvis0 for ; Tue, 20 Jul 2010 06:22:41 -0700 (PDT) Received: from mailsrv.i.zmi.at (h081217106033.dyn.cm.kabsi.at [81.217.106.33]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client CN "mailsrv2.i.zmi.at", Issuer "power4u.zmi.at" (not verified)) by mailsrv14.zmi.at (Postfix) with ESMTPSA id 30873400 for ; Tue, 20 Jul 2010 15:22:40 +0200 (CEST) Received: from saturn.localnet (saturn.i.zmi.at [10.72.27.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mailsrv.i.zmi.at (Postfix) with ESMTPSA id 1D9A783C82E for ; Tue, 20 Jul 2010 15:21:52 +0200 (CEST) From: Michael Monnerie Subject: Re: Calculating swidth On A RAID6 Volume Date: Tue, 20 Jul 2010 15:22:39 +0200 References: <3C5E029826A0704DB5998577FCFF46F0094DA1AD69@dagobah> In-Reply-To: <3C5E029826A0704DB5998577FCFF46F0094DA1AD69@dagobah> MIME-Version: 1.0 Message-Id: <201007201522.39455@zmi.at> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============5827399262338136230==" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com --===============5827399262338136230== Content-Type: multipart/signed; boundary="nextPart1947574.QRppP5lvmP"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit --nextPart1947574.QRppP5lvmP Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Dienstag, 20. Juli 2010 Andrew Debenham wrote: > I'm am new to XFS and am in the process of trying to tune an XFS file > system. I spent some time searching through this mailing list's > archives but wasn't able to find anything that matched the question > that I have (I apologize in advance if this issue has already been > addressed). Thanks for reminding me, wanted to write a FAQ entry, done now: http://xfs.org/index.php/XFS_FAQ#Q:_How_to_calculate_the_correct_sunit.2Csw= idth_values_for_optimal_performance > I have a 3ware 9650SE-12M installed and have a RAID6 unit with 11 x > 1.82 TB SATA drives and stripe size of 256KB. I found an earlier > thread that discussed calculating the values for sunit and swidth > for RAID5, which stated that the swidth would be "sunit x (# disks > in stripe - 1)". So, finally the question - would the swidth for a > RAID6 volume be "sunit x (# disks in stripe -2)? >=20 > If that is the case, then here is what I would expect my values to > be: sunit =3D 512 > swidth =3D 4608 =20 I think sunit should be as big as the RAID controllers stripe size, as=20 it describes the smallest I/O XFS should do. So sunit=3D512 would make it=20 possible that XFS writes a single sector, while the RAID controller=20 needs to read/write 256KB with your stripe size, resulting in=20 performance degradation. But I'm no XFS dev, so maybe wait for a=20 clearing from someone who has deeper XFS knowledge than me. sunit=3D262144 swidth=3D9 Would be my suggestion for your setup. =2D-=20 mit freundlichen Gr=C3=BCssen, Michael Monnerie, Ing. BSc it-management Internet Services http://proteger.at [gesprochen: Prot-e-schee] Tel: 0660 / 415 65 31 ****** Aktuelles Radiointerview! ****** http://www.it-podcast.at/aktuelle-sendung.html // Wir haben im Moment zwei H=C3=A4user zu verkaufen: // http://zmi.at/langegg/ // http://zmi.at/haus2009/ --nextPart1947574.QRppP5lvmP Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.12 (GNU/Linux) iEYEABECAAYFAkxFox8ACgkQzhSR9xwSCbQoqgCgoM/lymsAY6MtAx1G+Qs9OGDS HksAn170J++BL/No26f1qis0hG51yO/w =Z8UG -----END PGP SIGNATURE----- --nextPart1947574.QRppP5lvmP-- --===============5827399262338136230== 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 --===============5827399262338136230==--