From mboxrd@z Thu Jan  1 00:00:00 1970
From: Milan Broz <mbroz@redhat.com>
Subject: Re: FW: the mirror log is NOT kept on disk
Date: Mon, 21 Mar 2011 14:26:40 +0100
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On 03/21/2011 02:10 PM, Eli Malul wrote:

> But I still do not understand how should I create a mapped device
> with dmsetup tool which wouldl survive crash/reboot.

You cannot do that without implementing persistent metadata handling
yourself.

Use LVM here. dmsetup is simple wrapper to DM-ioctl, low level utility.

LVM is based on top of that and solves all the problems with persistent
metadata you just found.

Milan