From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 25 Jun 2012 17:27:03 +0100 From: Alasdair G Kergon Message-ID: <20120625162703.GC17857@agk-dp.fab.redhat.com> References: <4FE8770C.7090502@shiftmail.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4FE8770C.7090502@shiftmail.org> Subject: Re: [linux-lvm] Still missing for supporting dm-thin 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" Content-Transfer-Encoding: 7bit To: Spelic Cc: linux-lvm@redhat.com On Mon, Jun 25, 2012 at 04:34:52PM +0200, Spelic wrote: > 1) It is not possible to backup and restore a VG config (vgcfgrestore in > particular refuses to work) if there is a dm-thin volume. This is a very > serious problem that does not allow to recover even non-thin volumes if > there is a thin volume around. Even automatic backups from > /etc/lvm/archive cannot be restored/used. This puts data at risk, please > fix this. We do want to find a way to do this for non-thin volumes - the current restrictions are indeed tighter than they need to be. For thin volumes though it's a complex problem to work out what can be restored safely and what can't. (The metadata saying where a volume is is now split between the LVM metadata and the thin metadata.) > 2) less important: it is apparently not possible to change the --zero > flag for a thin pool once created. That should be just another lvchange parameter. Alasdair