From owner-freebsd-questions@FreeBSD.ORG Fri Jun 28 22:37:03 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id F17C13F8 for ; Fri, 28 Jun 2013 22:37:03 +0000 (UTC) (envelope-from nzp@riseup.net) Received: from mx1.riseup.net (mx1.riseup.net [198.252.153.129]) by mx1.freebsd.org (Postfix) with ESMTP id D67ED1A78 for ; Fri, 28 Jun 2013 22:37:03 +0000 (UTC) Received: from fruiteater.riseup.net (fruiteater-pn.riseup.net [10.0.1.74]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*.riseup.net", Issuer "Gandi Standard SSL CA" (not verified)) by mx1.riseup.net (Postfix) with ESMTPS id 6BD1744094; Fri, 28 Jun 2013 15:37:03 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: nzp@fruiteater.riseup.net) with ESMTPSA id 43BCCBB3 Date: Sat, 29 Jun 2013 00:36:59 +0200 From: Nikola =?utf-8?B?UGF2bG92acSH?= To: Charles Swiger Subject: Re: Troubleshooting a gmirror disk marked broken Message-ID: <20130628223659.GB15414@sputnjik.localdomain> Mail-Followup-To: Charles Swiger , Adam Vande More , FreeBSD Questions References: <20130627023837.GA7685@sputnjik.localdomain> <36C962B9-ABC4-45E3-AC94-46D6CEE960E1@mac.com> <0469490B-A577-40DA-9A04-910150330E16@mac.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0469490B-A577-40DA-9A04-910150330E16@mac.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Virus-Scanned: clamav-milter 0.97.8 at mx1 X-Virus-Status: Clean Cc: Adam Vande More , FreeBSD Questions X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Jun 2013 22:37:04 -0000 On Thu, Jun 27, 2013 at 10:06:45AM -0700, Charles Swiger wrote: > Hi-- > > On Jun 27, 2013, at 9:58 AM, Adam Vande More wrote: > > On Thu, Jun 27, 2013 at 10:16 AM, Charles Swiger wrote: > >> If you haven't rebuilt the mirror already, running a full disk read scan > >> against both drives (ie, via "dd if=/dev/ad4 of=/dev/null bs=1m" or similar) > >> might be prudent. That will help identify/migrate any sectors which are > >> failing but still recoverable via ECC to the spare sectors. > > > > I was going to say something like that too but AFAIK sectors aren't remapped on failed reads, has to be written to(dd if=/dev/zero of=/dev/ad4 bs=1m). If it were me, I make sure I had fully tested complete backups before I broke the mirror and did that. > > > If the drive reads a sector with ECC-correctable errors, it's supposed to try to re-write that sector in order to fix up the ECC data. If that write fails, it remaps. > > Of course, your suggestion of blanking the entire drive and restoring from the mirror or a backup would be best, or perhaps "better short of replacing the drive". > OK, thank you both for suggestions. It rebuilt fine, and it's working fine. If it starts giving me trouble again I'll try your suggestions, or, ultimately, ask to get the disk replaced (although I don't expect a much better replacement, it's one of those cheap rental servers, you get what you pay :)) I'm still a bit reluctant to run the ports tree update again, but I'll ask on -ports@ for further assistance with that. -- Writing free verse is like playing tennis with the net down.