From owner-freebsd-questions@FreeBSD.ORG Thu Jul 16 22:12:30 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2DF73106564A for ; Thu, 16 Jul 2009 22:12:30 +0000 (UTC) (envelope-from mkhitrov@gmail.com) Received: from mail-gx0-f217.google.com (mail-gx0-f217.google.com [209.85.217.217]) by mx1.freebsd.org (Postfix) with ESMTP id AB5A78FC15 for ; Thu, 16 Jul 2009 22:12:29 +0000 (UTC) (envelope-from mkhitrov@gmail.com) Received: by gxk17 with SMTP id 17so689972gxk.19 for ; Thu, 16 Jul 2009 15:12:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :from:date:message-id:subject:to:cc:content-type :content-transfer-encoding; bh=y48DHkByOsKt3UCM2kkaIgFeAgFhLAhqVWNhZ17XJrs=; b=fn4DPFKEa3pJdp4AWj4h2mHjFlPJU6yT1GzY+Z5G4jiUfIZuJSjrmVdYvqQHovyRqs 6dPLXSr3Da7d9Fg3ay9yfG/tVQEsvTV8RRo+dCK7VKLANtGCknZHPDRCuE+iOoUAnBpo VYiwLfe/t6e4Srq3urgDuP+aa2MBLDQBtJ5o8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=StAyaffVETLsBCFKARQnBZ6ZKeiMSsK2TUgwxvMZd1J6kvkK2IyNU4NsAtU30uxMtX GRYjULpL+dEibxtuKpGp9Xpa3A4qQCq0m807WZLEDk6YrSS0XkSbM6GV4PJsI11Gk5CL gT32o5O3AkL6BsKuP8yR5YFwSGLwFI9ec47xQ= MIME-Version: 1.0 Received: by 10.90.50.5 with SMTP id x5mr209860agx.56.1247782349078; Thu, 16 Jul 2009 15:12:29 -0700 (PDT) In-Reply-To: <458986.60331.qm@web51004.mail.re2.yahoo.com> References: <458986.60331.qm@web51004.mail.re2.yahoo.com> From: Maxim Khitrov Date: Thu, 16 Jul 2009 18:12:09 -0400 Message-ID: <26ddd1750907161512u109a4e49nc30ebc78bea5b8f@mail.gmail.com> To: mahlerrd@yahoo.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: Free BSD Questions list , Tom Worster Subject: Re: ZFS or UFS for 4TB hardware RAID6? 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: Thu, 16 Jul 2009 22:12:30 -0000 On Mon, Jul 13, 2009 at 4:08 PM, Richard Mahlerwein wro= te: >> > Just as a question: how ARE you planning on backing >> this beast up? =C2=A0While I don't want to sound like a >> worry-wort, I have had odd things happen at the worst of >> times. =C2=A0RAID cards fail, power supplies let out the magic >> smoke, users delete items they really want back... *sigh* >> >> Rsync over ssh to another server. Most of the data stored >> will never >> change after the first upload. A daily rsync run will >> transfer one or >> two gigs at the most. History is not required for the same >> reason; >> this is an append-only storage for the most part. A backup >> for the >> previous day is all that is required, but I will keep a >> weekly backup >> as well until I start running out of space. >> >> > A bit of reading shows that ZFS, if it's stable >> enough, has some really great features that would be nice on >> such a large pile o' drives. >> > >> > See http://wiki.freebsd.org/ZFSQuickStartGuide >> > >> > I guess the last question I'll ask (as any more may >> uncover my ignorance) is if you need to use hardware RAID at >> all?=C2=A0 It seems both UFS2 and ZFS can do software RAID >> which seems to be quite reasonable with respect to >> performance and in many ways seems to be more robust since >> it is a bit more portable (no specialized hardware). >> >> I've thought about this one a lot. In my case, the hard >> drives are in >> a separate enclosure from the server and the two had to be >> connected >> via SAS cables. The 9690SA-8E card was the best choice I >> could find >> for accessing an external SAS enclosure with support for 8 >> drives. >> >> I could configure it in JBOD mode and then use software to >> create a >> RAID array. In fact, I will likely do this to compare >> performance of a >> hardware vs. software RAID5 solution. The ZFS RAID-Z option >> does not >> appeal to me, because the read performance does not benefit >> from >> additional drives, and I don't think RAID6 is available in >> software. >> For those reasons I'm leaning toward a hardware >> implementation. >> >> If I go the hardware route, I'll try to purchase a backup >> controller >> in a year or two. :) >> >> > There are others who may respond with better >> information on that front.=C2=A0 I've been a strong >> proponent of hardware RAID, but have recently begun to >> realize many of the reasons for that are only of limited >> validity now. >> >> Agreed, and many simple RAID setups (0, 1, 10) will give >> you much >> better performance in software. In my case, I have to have >> some piece >> of hardware just to get to the drives, and I'm guessing >> that hardware >> RAID5/6 will be faster than the closest software >> equivalent. Maybe my >> tests will convince me otherwise. >> >> - Max > > I'd love to hear about any test results you may get comparing software wi= th hardware raid. I received the hardware yesterday. There was a last minute change due to cost. Instead of getting 4x 2TB drives I opted for 6x 1TB. This limits my future expansion a bit, but that may be a few years down the line. On the plus side, I can get the 4TB of RAID6 that I originally planned for and the performance should be better because of additional disks in the array. Sometime next week I'll install FreeBSD 8 and will then be able to run a few benchmarks. After that I'll configure software RAID and repeat the process. Are there any specific tests that you guys would like me to run? Sequential read/write tests using dd are a given, beyond that I'm not familiar with any ports under benchmarks/, so if you know of anything good, tell me. - Max