From owner-freebsd-questions@FreeBSD.ORG Fri Jul 21 12:06:13 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8AA9216A4DE for ; Fri, 21 Jul 2006 12:06:13 +0000 (UTC) (envelope-from daniel@copyleft.no) Received: from mail9.copyleft.no (mail9.copyleft.no [82.117.37.109]) by mx1.FreeBSD.org (Postfix) with ESMTP id 32A5243D45 for ; Fri, 21 Jul 2006 12:06:12 +0000 (GMT) (envelope-from daniel@copyleft.no) Received: from [82.117.37.67] (helo=[10.0.0.170]) by mail9.copyleft.no with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.60 (FreeBSD)) (envelope-from ) id 1G3tm2-0004bt-JT for freebsd-questions@freebsd.org; Fri, 21 Jul 2006 12:06:30 +0000 Message-ID: <44C0C32E.8060900@copyleft.no> Date: Fri, 21 Jul 2006 14:06:06 +0200 From: "Hr. Daniel Mikkelsen" User-Agent: Thunderbird 1.5.0.2 (X11/20060522) MIME-Version: 1.0 To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Slow RAID1 with gmirror X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Jul 2006 12:06:13 -0000 Hi. I've been setting up some gmirror based software RAID1s lately, and I keep running into some odd behaviour. Writing to the RAID1 runs at near to normal rates, as expected. But reading from the RAID1 runs at half the normal rates, while I expected to get double rates. I've tested this on 6.0, 6.1, with PATA and SATA drives, and I consistently get the same results. I've tested with the same hardware running Linux 2.6 with software RAID1 and there I get the expected double rate. I've tried all the available balance algorithms, and none of them help. I haven't tried with SCSI disks. I'm thinking that it might be the test I'm running that's a corner case, I simply dd to or from the filesystem with various settings for bs=. Is this a know issue? Is it an issue at all? -- Daniel Mikkelsen Copyleft Software AS