From owner-freebsd-scsi@FreeBSD.ORG Sat Nov 26 19:42:11 2005 Return-Path: X-Original-To: freebsd-scsi@freebsd.org Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0713716A41F for ; Sat, 26 Nov 2005 19:42:11 +0000 (GMT) (envelope-from amon@sockar.homeip.net) Received: from sockar.homeip.net (tourist.net8.nerim.net [213.41.176.3]) by mx1.FreeBSD.org (Postfix) with ESMTP id ECECB43D81 for ; Sat, 26 Nov 2005 19:41:56 +0000 (GMT) (envelope-from amon@sockar.homeip.net) Received: from sockar.homeip.net (localhost [127.0.0.1]) by sockar.homeip.net (8.13.3/8.13.3) with ESMTP id jAQJfqVd004677; Sat, 26 Nov 2005 20:41:52 +0100 (CET) (envelope-from amon@sockar.homeip.net) Received: (from amon@localhost) by sockar.homeip.net (8.13.3/8.13.3/Submit) id jAQJfqtJ004676; Sat, 26 Nov 2005 20:41:52 +0100 (CET) (envelope-from amon) Date: Sat, 26 Nov 2005 20:41:52 +0100 From: Herve Boulouis To: user Message-ID: <20051126194152.GA594@ra.aabs> References: Mime-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.4.2.1i Cc: freebsd-scsi@freebsd.org Subject: Re: configuration choices with Dell CERC (adaptec 2610SA) X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 26 Nov 2005 19:42:11 -0000 Le 26/11/2005 14:17, user a écrit: > > Read caching: yes/no (default is yes) > > (read caching does not rely on a battery, and is completely "safe", > right? I am going to set this to "yes", however I wonder - why would > anyone _ever_ set it to "no" ?) You usually want to disable read caching on all aac based adaptec raid controllers because it decreases performance. > Write caching: enable/disable > > (this is the one that can get you into trouble if the system loses power > before a write is committed to disk, and the battery is dead, right? I am > going to set this to "disable" because I do not think the 2610SA has a > battery ... right ?) If your server is plugged on a UPS you can safely enable it, it's quite a performance gain. > Rebuild rate: high/medium/low > > (I have no idea what this means - I never saw this in adaptec bios before > ... can anyone define exactly what this means ?) This controls how much ressources the card will put in rebuilding a volume that got a failed disk. A high rebuild rate will mean a short rebuild time but slower disk accesses during the rebuild. -- Herve Boulouis