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 m41IFKXu012826 for ; Thu, 1 May 2008 14:15:20 -0400 Received: from vms173005pub.verizon.net (vms173005pub.verizon.net [206.46.173.5]) by mx3.redhat.com (8.13.8/8.13.8) with ESMTP id m41IF9rZ008113 for ; Thu, 1 May 2008 14:15:09 -0400 Received: from [192.168.2.102] ([72.91.189.24]) by vms173005.mailsrvcs.net (Sun Java System Messaging Server 6.2-6.01 (built Apr 3 2006)) with ESMTPA id <0K0700LR3BRBUMD1@vms173005.mailsrvcs.net> for linux-lvm@redhat.com; Thu, 01 May 2008 13:09:11 -0500 (CDT) Date: Thu, 01 May 2008 14:15:03 -0400 From: Gerry Reno Subject: Re: [linux-lvm] F7 will not boot after running backup w/snapshot In-reply-to: Message-id: <481A08A7.5010305@verizon.net> MIME-version: 1.0 Content-transfer-encoding: 7bit References: <4817C2FD.1010909@verizon.net> <4817D97D.8060805@verizon.net> <4817ECAF.4020806@verizon.net> <48187B91.4060901@verizon.net> <1c748a490804300809s304f7fdfx55aeb0fd9c6cc7ab@mail.gmail.com> <4818AB1C.9030809@verizon.net> <4818BA5D.6070501@Media-Brokers.com> <4818D59A.8020906@verizon.net> <4818E262.4070105@redhat.com> <4818F2FC.5050907@verizon.net> <20080501154800.GA5941@us.ibm.com> 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 Mikulas Patocka wrote: > ... If you mount the origin device with missing snapshot, you destroy > the snapshot (even if you don't touch it). The snapshot can no longer > be repaired. > > So it is safer to not activate device in this case then destroy data. Why? What value is the old snapshot at this point? You just had a system reboot in the middle of a snapshotted backup so all you need to do is get the system up, redo another snapshot and retake your backup. I'm not interested in the old snapshot. > > Imagine, for example, you have origin and snapshot, you reconfigure > disks in some weird way that the snapshot disk is inaccessible, you > boot, and the system automatically starts without the snapshot. And > you lose any data that you stored on that snapshot. What is on the old snapshot at this point is probably indeterminate anyway. > You can with dmsetup (but it has deadlocks). Maybe someone could write > non-deadlocky snapshot-managing tool that wouldn't depend on lvm vgs, > pvs and lvs. > > Mikulas Have not used dmsetup. If it has deadlocks, I don't think I want to use it. Gerry