From owner-freebsd-hardware@FreeBSD.ORG Mon Nov 17 03:15:51 2008 Return-Path: Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CCC341065670; Mon, 17 Nov 2008 03:15:51 +0000 (UTC) (envelope-from fbsd@dannysplace.net) Received: from mail.dannysplace.net (mail.dannysplace.net [213.133.54.210]) by mx1.freebsd.org (Postfix) with ESMTP id 7F2D88FC13; Mon, 17 Nov 2008 03:15:51 +0000 (UTC) (envelope-from fbsd@dannysplace.net) Received: from 203-206-171-212.perm.iinet.net.au ([203.206.171.212] helo=[192.168.10.10]) by mail.dannysplace.net with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.69 (FreeBSD)) (envelope-from ) id 1L1uaR-0001qd-Da; Mon, 17 Nov 2008 13:15:50 +1000 Message-ID: <4920E1DD.7000101@dannysplace.net> Date: Mon, 17 Nov 2008 13:15:41 +1000 From: Danny Carroll User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 To: =?ISO-8859-1?Q?Eirik_=D8verby?= References: <490A782F.9060406@dannysplace.net> <20081031033208.GA21220@icarus.home.lan> <490A849C.7030009@dannysplace.net> <20081031043412.GA22289@icarus.home.lan> <490A8FAD.8060009@dannysplace.net> <491BBF38.9010908@dannysplace.net> <491C5AA7.1030004@samsco.org> <491C9535.3030504@dannysplace.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Authenticated-User: danny X-Authenticator: plain X-Sender-Verify: SUCCEEDED (sender exists & accepts mail) X-Exim-Version: 4.69 (build at 08-Jul-2008 08:59:40) X-Date: 2008-11-17 13:15:39 X-Connected-IP: 203.206.171.212:1568 X-Message-Linecount: 40 X-Body-Linecount: 26 X-Message-Size: 2082 X-Body-Size: 1202 X-Received-Count: 1 X-Recipient-Count: 3 X-Local-Recipient-Count: 3 X-Local-Recipient-Defer-Count: 0 X-Local-Recipient-Fail-Count: 0 X-SA-Exim-Connect-IP: 203.206.171.212 X-SA-Exim-Rcpt-To: ltning@anduin.net, freebsd-fs@freebsd.org, freebsd-hardware@freebsd.org X-SA-Exim-Mail-From: fbsd@dannysplace.net X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on ferrari.dannysplace.net X-Spam-Level: X-Spam-Status: No, score=0.2 required=8.0 tests=ALL_TRUSTED,AWL,TVD_RCVD_IP autolearn=disabled version=3.2.5 X-SA-Exim-Version: 4.2 X-SA-Exim-Scanned: Yes (on mail.dannysplace.net) Cc: freebsd-fs@freebsd.org, freebsd-hardware@freebsd.org Subject: Re: Areca vs. ZFS performance testing. X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: fbsd@dannysplace.net List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Nov 2008 03:15:51 -0000 Eirik Øverby wrote: > I have noticed that my 3ware controllers, after updating firmware > recently, have removed the JBOD option entirely, classifying it as > something you wouldn't want to do with that kind of hardware anyway. I > believed then, and even more so now, they are correct. It kinda depends. If there were a good 8 or 16+ port SATA card out there that *simply* did SATA with no bells and whistles, then there would be no point buying a Raid adaptor when you want to use things like ZFS. But there are no such cards available. > Use the RAID-0 disk trick to be able to utilize the controller cache. > And regarding write-back vs write-through; I believe write-through is > equvivalent to disabling controller write cache, however it WILL cache > the writes in order to respond to future reads of the data being > written. I would guess, but I don't know, that this also goes for > disk-level caches too, though, so it probably doesn't matter. It is interesting to me that the default setting on the Areca card was to have the disk caches turned on. I think that is strange because by default you have a situation that can lead to data loss even if you have a battery backup unit. -D