From owner-freebsd-questions@FreeBSD.ORG Thu Jun 27 17:06:49 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 146E5D54 for ; Thu, 27 Jun 2013 17:06:49 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from st11p05mm-asmtp001.mac.com (st11p05mm-asmtpout004.mac.com [17.172.108.249]) by mx1.freebsd.org (Postfix) with ESMTP id E23A912BD for ; Thu, 27 Jun 2013 17:06:48 +0000 (UTC) Received: from vp2a02a-dhcp125.apple.com (unknown [17.209.11.125]) by st11p05mm-asmtp001.mac.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Jan 3 2012)) with ESMTPSA id <0MP200GPAA7A1K10@st11p05mm-asmtp001.mac.com> for freebsd-questions@freebsd.org; Thu, 27 Jun 2013 17:06:48 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.10.8794,1.0.431,0.0.0000 definitions=2013-06-27_07:2013-06-27,2013-06-27,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=6.0.2-1305010000 definitions=main-1306270133 Content-type: text/plain; charset=iso-8859-1 MIME-version: 1.0 (Mac OS X Mail 6.5 \(1508\)) Subject: Re: Troubleshooting a gmirror disk marked broken From: Charles Swiger In-reply-to: Date: Thu, 27 Jun 2013 10:06:45 -0700 Content-transfer-encoding: quoted-printable Message-id: <0469490B-A577-40DA-9A04-910150330E16@mac.com> References: <20130627023837.GA7685@sputnjik.localdomain> <36C962B9-ABC4-45E3-AC94-46D6CEE960E1@mac.com> To: Adam Vande More X-Mailer: Apple Mail (2.1508) Cc: =?utf-8?Q?Nikola_Pavlovi=C4=87?= , 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: Thu, 27 Jun 2013 17:06:49 -0000 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=3D/dev/ad4 of=3D/dev/null bs=3D1m" = or similar) >> might be prudent. That will help identify/migrate any sectors which = are >> failing but still recoverable via ECC to the spare sectors. >=20 > 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=3D/dev/zero = of=3D/dev/ad4 bs=3D1m). 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". Regards, --=20 -Chuck