From mboxrd@z Thu Jan 1 00:00:00 1970 From: "S. J. van Harmelen" Subject: Re: Use LVM on /dev/mapper/diskname and iSCSI Date: Mon, 19 Nov 2007 22:19:53 +0100 Message-ID: <1195507193.11489.27.camel@sanderbal> References: <1195480602.6074.3.camel@sanderbal> <47419854.2000508@linpro.no> <1195484847.6074.16.camel@sanderbal> <4741D96F.7080502@linpro.no> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4741D96F.7080502@linpro.no> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids Tore, Please take a look at my reply to Malaha. This is also a reply to your message... Hope you have the time to read it. Thanks, Sander On Mon, 2007-11-19 at 19:43 +0100, Tore Anderson wrote: > * S. J. van Harmelen > > > Thanks for your help! > > > > I executed the pvs command and it did find a few partitions. I use > > iSCSI to share the LUN's to a XenSource server, and XenSource creates > > the PV's and LV's in order to provision VM's. Didn't think of that, > > but that's on the disk of course. > > > > Is there any way to configure snapshots for these already created LVM > > partitions? Or do I have to whipe the disk clean (rather not do > > that, but if I have to it can be done), then create the pv's and lv's > > and then share the lv's true iSCSI? > > > > In that case XenSource will again create pv's and lv's in the shared > > lv. Ain't that a problem? > > You really need a filter line in /etc/lvm/lvm.conf, to keep LVM from > claiming 1) individual paths to a dm-multipath controlled LUN, and 2) > LUNs that are PVs used by the LVM implementation in your domUs. > > You don't want LVM to be claiming the paths directly, because you'd no > longer have any redundancy - it will override dm-multipath. You also > don't want the LVM implementation in your dom0 to be using the same > block device as LVM in your domU as physical volumes, as LVM is designed > to have exclusive access to its PVs (you might get around this with > CLVM, though). > > Do I understand correctly if you have one LUN that contains your domO > (having its file systems in LVs), and several LUNs that contain your > domUs, which again are PVs that are supposed to be used by your domU > kernels? > > If so you will want to keep your dom0 from claiming the domU PVs. Use a > filter line that accepts only the multipath'ed volume that contains the > dom0 installation, and drop the rest. For instance: > > filter = [ "a|^/dev/mapper/domzero$", "r|.*" ] > > ...assuming your dom0 data volume is called "domzero" in multipath.conf. > > Regards