From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 28 Aug 2001 09:51:04 +0100 Subject: Re: [linux-lvm] Pvmove question Message-ID: <20010828095104.E283@btconnect.com> References: Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: ; from corryk@us.ibm.com on Mon, Aug 27, 2001 at 08:46:33AM -0500 From: Joe Thornber Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@sistina.com On Mon, Aug 27, 2001 at 08:46:33AM -0500, Kevin M Corry wrote: > > On Fri, Aug 24, 2001 at 12:31:18AM +0200, Jean-Eric Cuendet wrote: > > > > > > Hi, > > > I have a pvmove question: > > > In the man page, it's said to be careful with pvmove if you use it > while > > > LVM is in use. > > > I don't really understand what is dangerous and what is safe... > > > > pvmove on a mounted (or otherwise in use) LV might cause curruption of > > your data. > > In what cases could pvmove cause corruption on a mounted LV? Looking > at the man page and scanning through pvmove.c, it seems to indicate > that only a system crash during pvmove would corrupt the data. Is > this the only case, or are there others? Search back through the list for a response from Andrea Arcangeli. We need to track buffer_heads that have been trhough the make_request function so we can really can flush the LV when suspending io for the dureation of the move. If you're not using raw io then the only problem is a possible deadlock when under high memory pressure. > If there are other possibilities for corruption, wouldn't it be a > good idea to not allow pvmove's on PV's that contain mounted LVs? IMO yes. - Joe