From owner-freebsd-questions@FreeBSD.ORG Fri Jan 2 21:01:01 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 A1728106564A for ; Fri, 2 Jan 2009 21:01:01 +0000 (UTC) (envelope-from davidn04@gmail.com) Received: from qw-out-2122.google.com (qw-out-2122.google.com [74.125.92.26]) by mx1.freebsd.org (Postfix) with ESMTP id 467A98FC25 for ; Fri, 2 Jan 2009 21:01:01 +0000 (UTC) (envelope-from davidn04@gmail.com) Received: by qw-out-2122.google.com with SMTP id 9so3889778qwb.7 for ; Fri, 02 Jan 2009 13:01:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=Rcsj4FpUPwqDC4FbWDjWD0Wrh1ebZvt05Qk88vEMbNk=; b=WyYdvgJBIR8vyGkzZlkRd0eaAzLMot1zfVXtjado9m0osQpZDvKwcbJtKEU6su5lcn cYbA1yg1CAsNbmTeCQQ/TomdznIbd5IOjVd3gmcyDX2WZekrUB+Ped/gjoa1mjYIB3ez z/mHUdmksK4UqloKCGENzqdOVXiSKfmn/sdvg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=FwvkrAUEmBQPkkfPYXQagkXuZSHscPQMgRK4nasdq4uLXwJ8Y1fGRuhuxBeJtP4les OBAVQcmfMKu1+/IYESCstqFrcAZZ7HH5DeGhYMnPvPHc5qsaDIChJMAyaWW36wZ+HOWM my6xKUPkjcaLLsOBFd5MRUrVr/nlMHqPIO6jE= Received: by 10.215.15.1 with SMTP id s1mr15346000qai.209.1230930060537; Fri, 02 Jan 2009 13:01:00 -0800 (PST) Received: by 10.214.81.4 with HTTP; Fri, 2 Jan 2009 13:01:00 -0800 (PST) Message-ID: <4d7dd86f0901021301o10f49edbj1e103ab336ab409c@mail.gmail.com> Date: Sat, 3 Jan 2009 08:01:00 +1100 From: "David N" To: "Frederique Rijsdijk" In-Reply-To: <495E17AD.30707@isafeelin.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <495E17AD.30707@isafeelin.org> Cc: freebsd-questions@freebsd.org Subject: Re: Using HDD's for ZFS: 'desktop' vs 'raid / enterprise' -edition drives? 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, 02 Jan 2009 21:01:02 -0000 2009/1/3 Frederique Rijsdijk : > Hi freebsd-questions, > > For personal use (photo/video storage), I'm looking into creating a huge > single ZFS (raidz) volume that will replace my current collection of > drives used as storage. I'm thinking 4*1TB drives in RAID5(z). > > My question is regarding the flavour of drivers that one can choose > from: Desktop class drives, or the so called RAID/Enterprise class drives. > > The difference between the two being the way such a drive handles the > bad-sector/block handling and remapping. I understand that Desktop class > drives do all this internally, and this is a process that can take up to >> >> 60s (even minutes on some), and during this process the drive is > > unavailable to the controller. The RAID edition drives all appoach this > differently and alot faster, typically before 8 seconds. > > How does ZFS handle this? Should I be looking for the RAID class drives > or can Desktop class drives be used here? > > My worry is of course that such a drive (destkop class) will be marked > defective and thrown out of the raid volume if a remapping of bad > sectors occurs and the drive will be unresponsive to the controller/ZFS > for > 8 seconds. > > Some drives can be configured in this area, but not all, and there's > quite a price difference in the two, the desktop class being up to 50% > cheaper in some cases.. > > Anybody that can shed some light on this? > > > Thanks, > > -- Frederique Hi, Before i knew the difference between the two, i got myself a bunch of "desktop" HDD. From what I've experience, freebsd just drops the drive. (Currently running in a gmirror config). I'm not sure about ZFS, but i would assume it would do the same. All you need to the do reattach the drive and it will sync back up again. I didn't know the reason why it dropped off, but when i checked the SMART, it showed 1 bad sector reallocation. If it happens to a disk with UFS, it crashes and restarts the machine, UFS doesn't like disappearing drives. Regards David N