From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n3GDBbF9003358 for ; Thu, 16 Apr 2009 09:11:39 -0400 Received: from mx03.syneticon.net (mx03.syneticon.net [78.111.66.105]) by mx3.redhat.com (8.13.8/8.13.8) with ESMTP id n3GCR41d031241 for ; Thu, 16 Apr 2009 08:27:05 -0400 Received: from localhost (filter1.syneticon.net [192.168.113.83]) by mx03.syneticon.net (Postfix) with ESMTP id 141DD3614B for ; Thu, 16 Apr 2009 14:27:01 +0200 (CEST) Received: from mx03.syneticon.net ([192.168.113.84]) by localhost (mx03.syneticon.net [192.168.113.83]) (amavisd-new, port 10025) with ESMTP id J5ZTGpTgrav2 for ; Thu, 16 Apr 2009 14:26:59 +0200 (CEST) Received: from [192.168.10.145] (koln-5d818dc1.pool.einsundeins.de [93.129.141.193]) by mx03.syneticon.net (Postfix) with ESMTPSA for ; Thu, 16 Apr 2009 14:26:59 +0200 (CEST) Message-ID: <49E72412.1070407@wpkg.org> Date: Thu, 16 Apr 2009 14:26:58 +0200 From: Tomasz Chmielewski MIME-Version: 1.0 Subject: Re: [linux-lvm] Simulating LVM Mirror Failure and recovery References: <29070.706.qm@web94806.mail.in2.yahoo.com> <49E71F9D.3010401@sivell.com> In-Reply-To: <49E71F9D.3010401@sivell.com> Content-Transfer-Encoding: 7bit Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development vu pham schrieb: >> as per the redhat guide this should result in mirror leg failure and >> any subsequent write activity to the mirror should convert the mirror >> into linear volume. but the output of lvs command still shows copy % >> as 100%. also data in filesystem of lv1 is erased and it is converted >> into read only filesystem. >> >> can anyone please let us know the correct way to simulate lvm mirror >> failure and recovery. >> >> thanks and regards > > I think to simulate error failure you have to write to the underlying > devices, not the mirrored device. When you write to the mirrored device, > lvl1 in this case, data is mirrored so there is no failure at all. So I > think you have to dd to either /dev/sda3 or /dev/sdb3. How will LVM distinguish between a valid and invalid copy in that case? Are you sure that on reads, LVM will return data from the "good" copy, not the one you just overwrote with "dd if=/dev/zero of=/dev/sdb seek=xxx bs=1M count=10"? -- Tomasz Chmielewski http://wpkg.org