From owner-freebsd-hackers@FreeBSD.ORG Mon Feb 13 16:51:46 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C7252106564A for ; Mon, 13 Feb 2012 16:51:46 +0000 (UTC) (envelope-from freebsd-hackers@m.gmane.org) Received: from plane.gmane.org (plane.gmane.org [80.91.229.3]) by mx1.freebsd.org (Postfix) with ESMTP id 7923A8FC1C for ; Mon, 13 Feb 2012 16:51:46 +0000 (UTC) Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Rwz7x-0001hj-BX for freebsd-hackers@freebsd.org; Mon, 13 Feb 2012 17:51:45 +0100 Received: from lara.cc.fer.hr ([161.53.72.113]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 13 Feb 2012 17:51:45 +0100 Received: from ivoras by lara.cc.fer.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 13 Feb 2012 17:51:45 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-hackers@freebsd.org From: Ivan Voras Date: Mon, 13 Feb 2012 17:51:35 +0100 Lines: 49 Message-ID: References: <4F3922A8.2090808@softhammer.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig30C27DE334A3890B8C08E44E" X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: lara.cc.fer.hr User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:10.0) Gecko/20120213 Thunderbird/10.0 In-Reply-To: <4F3922A8.2090808@softhammer.net> X-Enigmail-Version: 1.3.5 Subject: Re: Odd RAID Performance Issue X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Feb 2012 16:51:46 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig30C27DE334A3890B8C08E44E Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 13/02/2012 15:48, Stephen Sanders wrote: > We've an application that logs data on one very large raid6 array > and updates/accesses a database on another smaller raid5 array. You would be better off with RAID10 for a database (or anything which does random IO). > Both arrays are connected to the same PCIe 3ware RAID controller. The= > system has 2 six core 3Ghz processors and 24 GB of RAM. The system is > running FreeBSD 8.1. Did you do any additional OS tuning? Do you use UFS or ZFS? > The problem we're encountering is that the disk subsystem appears to > 'pause' periodically. It looks as if this is a result of disk read/wr= ite > operations from the database array taking a very long time to complete > (up to 8 sec). You should be able to monitor this with "iostat -x 1" (or whatever number of seconds instead of "1") - the last three columns should tell you if the device(s) are extraordinarily busy, and the r/s and w/s columns should tell you what the real IOPS rate is. You should probably post a sample output from this command when the problem appears. --------------enig30C27DE334A3890B8C08E44E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk85P5cACgkQldnAQVacBcjySgCfSpFYYZBfvTXUmAaC3ONDpAmO aVcAn3cTAUGdYVRiFIOm8l6lFSvU6eQ2 =xvj2 -----END PGP SIGNATURE----- --------------enig30C27DE334A3890B8C08E44E--