From owner-freebsd-questions@freebsd.org Wed Aug 3 20:29:20 2016 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8D421BAE7F5 for ; Wed, 3 Aug 2016 20:29:20 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from fly.hiwaay.net (fly.hiwaay.net [216.180.54.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 5C6311A28 for ; Wed, 3 Aug 2016 20:29:20 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from kabini1.local (dynamic-216-186-209-65.knology.net [216.186.209.65] (may be forged)) (authenticated bits=0) by fly.hiwaay.net (8.13.8/8.13.8/fly) with ESMTP id u73KTHR8004533 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Wed, 3 Aug 2016 15:29:18 -0500 Subject: Re: Ominous smartd messages .... To: freebsd-questions@freebsd.org References: <020caa94-b329-d5a6-5bd4-bfcc575c039f@freebsd.org> <4b35b969-606b-9084-5ce3-688eddfc5e70@FreeBSD.org> From: "William A. Mahaffey III" Message-ID: Date: Wed, 3 Aug 2016 15:34:47 -0453.75 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <4b35b969-606b-9084-5ce3-688eddfc5e70@FreeBSD.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.22 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Aug 2016 20:29:20 -0000 On 08/03/16 15:19, Matthew Seaman wrote: > On 03/08/2016 20:13, William A. Mahaffey III wrote: >> What does this mean ? > That there's a bad spot on the disk, which may also mean that you've got > a corrupted filesystem -- depends if the bad spot was in use by zfs or > not. 'zpool scrub' should tell you if the filesystem is corrupted. Can I do that 'zpool scrub' live ? > > Time to replace the drive. You should be able to convert the vdev that > contains the failing drive into a mirror temporarily, and sync the data > without downtime beyond maybe a few reboots to install the new disk > (assuming you have space to plug the new drive in without unplugging any > of the old ones). Failing that, you're going to need to rebuild the > zpool from scratch and restore your data from backup. No spare SATA slots :-/ .... > > Also, the fact that you have how ever many terabytes of data with no > resilience just makes me feel on edge -- and it's not even my data. > > Strongly recommend rebuilding your zpool as a RAIDZ of 8 drives -- yes, > you'll end up with less usable space, but you and your data will survive > failure of a drive and a 'zpool scrub' will be able to fix things even > if a bad spot on one drive has scrambled some of your data. I was/am already thinking along those lines, w/ 1 complication. I have another box (NetBSD 6.1.5) w/ a RAID5 that I wound up building w/ mis-aligned disk/RAID blocks in spite of a fair amount of effort to avoid that. I/O writes are horrible, 15-20 MB/s. My understanding is that RAIDZn is like RAID5 in many ways & that you always want 2^n+1 (3,5,9, ...) drives in a RAID5 to mitigate those misalignments, presumably in a RAIDZ also. Is that so w/ RAIDZ as well ? If so, I lose more than a small amount of total storage, which is why I went as I did when I built the box whenever that was. -- William A. Mahaffey III ---------------------------------------------------------------------- "The M1 Garand is without doubt the finest implement of war ever devised by man." -- Gen. George S. Patton Jr.