From owner-freebsd-fs@FreeBSD.ORG Wed Feb 5 18:42:49 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 7A5B6260 for ; Wed, 5 Feb 2014 18:42:49 +0000 (UTC) Received: from mail-pb0-x22f.google.com (mail-pb0-x22f.google.com [IPv6:2607:f8b0:400e:c01::22f]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 47C2F1A4A for ; Wed, 5 Feb 2014 18:42:49 +0000 (UTC) Received: by mail-pb0-f47.google.com with SMTP id rp16so719046pbb.20 for ; Wed, 05 Feb 2014 10:42:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :message-id:references:to; bh=EMsdV7eRaGHZcjDofPwjIIYAjGMzfY3xTResgRplUC8=; b=ReGReMUQv4EJHm3X76TJdSy3N8rQeBX0NRstZXJhz6TVa34ktmxZAN7Nq9r+mPPPoA 9HxO/pTIOb10+0jvBzmfQE78ZCKyUFPPx9H9J/BBBEccrLhHMpDN9CcViCMFrcabtLwP T2oBuXliztHMnhz77IlUor2+uIGqW/nzhyPgsDDxsY27J+h/ddrCRYoSG8y16+pW3VW5 KvsflWqOnurdINuza2YI7uOEwNbTvIq5MKsVHaChrZycfCRYle41nDjgz5JI0DBgVCXY s/nZtV411Z8NlZ1xMRjsLUbGRXzFMfthIfCNXHJrsqxYq+1J/02kjwuilScKrJzHXg2k w0oA== X-Received: by 10.68.203.135 with SMTP id kq7mr4141281pbc.85.1391625766837; Wed, 05 Feb 2014 10:42:46 -0800 (PST) Received: from briankrusicw.logan.tv ([64.17.255.138]) by mx.google.com with ESMTPSA id ja8sm38456191pbd.3.2014.02.05.10.42.45 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 05 Feb 2014 10:42:46 -0800 (PST) Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Subject: Re: practical maximum number of drives From: aurfalien In-Reply-To: <52F1FBBA.1000909@digsys.bg> Date: Wed, 5 Feb 2014 10:42:45 -0800 Message-Id: <785DBF11-1550-4918-B346-4843D7E2AF0B@gmail.com> References: <52F1BDA4.6090504@physics.umn.edu> <7D20F45E-24BC-4595-833E-4276B4CDC2E3@gmail.com> <52F1DEBC.9020304@digsys.bg> <52F1FBBA.1000909@digsys.bg> To: Daniel Kalchev X-Mailer: Apple Mail (2.1827) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: freebsd-fs X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Feb 2014 18:42:49 -0000 Cool. But I was more curious about what lead you to using 1 HBA over using a = few more. You mentioned something about interrupts, what problems manifested as a = result of multi HBAs? - aurf On Feb 5, 2014, at 12:52 AM, Daniel Kalchev wrote: > Ok, two things. >=20 > First, it was a typo -- the number is 122 devices and I actually got = it from the likes of this FAQ entry: = http://www.supermicro.com/support/faqs/faq.cfm?faq=3D10004 > I never use these for anything other than HBA. >=20 > It is interesting to see that LSI claims 3000 devices. Might be, = firmware has changed? Or there are different variations of the = chip/implementation? >=20 > Daniel >=20 > On 05.02.14 10:08, Rich wrote: >> The SAS2008 has a limit of 112 drives? >>=20 >> = http://www.lsi.com/downloads/Public/SAS%20ICs/LSISAS2008/SCG_LSISAS2008_PB= _043009.pdf >> claims "up to 3000 devices." >>=20 >> SAS2008 is a PCIe gen 2 x8 chip. >>=20 >> I suspect the bottleneck order would go SAS expander then SAS2008 = then PCIe. >>=20 >> - Rich >>=20 >> On Wed, Feb 5, 2014 at 1:48 AM, Daniel Kalchev = wrote: >>> I also wonder how you managed to go over the LSI2008's limit of 112 >>> drives... >>>=20 >>>=20 >>> On 05.02.14 07:36, aurfalien wrote: >>>> Hi Graham, >>>>=20 >>>> When you say behaved better with 1 HBA, what were the issues that = made you >>>> go that route? >>>>=20 >>>> Also, curious that you have that many drives on 1 PCI card, is it = PCI 3 >>>> etc... and is saturation an issue? >>>>=20 >>>> - aurf >>>>=20 >>>> On Feb 4, 2014, at 8:27 PM, Graham Allan = wrote: >>>>=20 >>>>> This may well be a question with no real answer but since we're = speccing >>>>> out a new ZFS-based storage system, I've been asked what the = maximum number >>>>> of drives it can support would be (for a hypothetical expansion = option). >>>>> While there are some obvious limits such as SAS addressing, I = assume there >>>>> must be more fundamental ones in the kernel or drivers, and the = practical >>>>> limits will be very different from the hypothetical ones. >>>>>=20 >>>>> So far the largest system we've built is using three 45-drive = chassis on >>>>> one SAS2008 (mps) controller, so 135 drives total. Over many = months of >>>>> running we had several drives fail and be replaced, and eventually = the OS >>>>> (9.1) failed to assign new da devices. It was time to patch the = system and >>>>> reboot anyway, which solved it, but we did wonder if we were = running into >>>>> some kind of limit around 150 drives - though I don't see why. >>>>>=20 >>>>> Interestingly we initially built this system with each drive = chassis on >>>>> its own SAS2008 HBA, but it ultimately behaved better = daisy-chained with >>>>> only one. I think I saw a hint somewhere this could be to do with = interrupt >>>>> sharing... >>>>>=20 >>>>> Thanks for any insights, >>>>>=20 >>>>> Graham >>>>> _______________________________________________ >>>>> freebsd-fs@freebsd.org mailing list >>>>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>>>> To unsubscribe, send any mail to = "freebsd-fs-unsubscribe@freebsd.org" >>>> _______________________________________________ >>>> freebsd-fs@freebsd.org mailing list >>>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>>> To unsubscribe, send any mail to = "freebsd-fs-unsubscribe@freebsd.org" >>>=20 >>>=20 >>> _______________________________________________ >>> freebsd-fs@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >>> To unsubscribe, send any mail to = "freebsd-fs-unsubscribe@freebsd.org" >=20 > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"