From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (ext-mx11.extmail.prod.ext.phx2.redhat.com [10.5.110.16]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p4AIZOWN001280 for ; Tue, 10 May 2011 14:35:24 -0400 Received: from qmail-admn-norm-0.netfirms.com (admin-norm-b.netfirms.com [70.35.17.200]) by mx1.redhat.com (8.14.4/8.14.4) with SMTP id p4AIZKXo021311 for ; Tue, 10 May 2011 14:35:21 -0400 Received: from steve by steve-desktop with local (Exim 4.69) (envelope-from ) id 1QJrnK-0008HO-4y for linux-lvm@redhat.com; Tue, 10 May 2011 14:36:30 -0400 Date: Tue, 10 May 2011 14:36:30 -0400 From: Steve Shorter Message-ID: <20110510183630.GA31792@netfirms.com> References: <20110509203822.GA29336@netfirms.com> <4DC85F38.5070506@spinn.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <4DC85F38.5070506@spinn.net> Subject: Re: [linux-lvm] creating pv's on LVM's for virtual guests 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: LVM general discussion and development On Mon, May 09, 2011 at 03:40:08PM -0600, allan wrote: > Hi Steve, > > I've had mixed results doing that very thing. Two servers perform very differently. > One mach, an HP DL380G6 w/ dual quad core Zeon and 6 146G disks installed > with CentOS 5.5 stock xen, lvm, etc. performs very well. Another machine > intended as a low class server, a desktop quad core AMD, 4 SATA disks > installed with stock CentOS 5.5 same as first mach, has issues with disk > perfomance on every DomU - writes are 1/10 the rate of Dom0 -- I'm still > troubleshooting it. > I see no problem with using LVM on Dom0, carving it up and offering to > DomU virtuals and the virtuals using LVM for storage. One thing to avoid: > do not duplicate an LVM names within the entire machine. i.e. installer, > when told to use LVM, will create a vg of a specific name. If this name > is not overridden, and you create multiple DomUs with same process the VG > name will be duplicated (as well as the LV names). Avoid name > duplication. > I hope this helps. > > Allan This is what I do on the host lvcreate --name ${DOMAIN} --size ${VSIZE}G ${HOST} || exit 2 pvcreate -y -ff /dev/${HOST}/${DOMAIN} || exit 3 vgcreate -y -ff -s32m ${DOMAIN} /dev/${HOST}/${DOMAIN} || exit 4 lvcreate --name data --size ${DISKSIZE} ${DOMAIN} || exit 5 lvcreate --name swap -l 100%FREE ${DOMAIN} || exit 6 mkfs.ext3 /dev/${DOMAIN}/data || exit 7 mkswap /dev/${DOMAIN}/swap || exit 8 I pass /dev/${HOST}/${DOMAIN} to the quest, and it sees a VG ${DOMAIN} with LV's named "data" and "swap" and they are immediately usable as swap/ext3 Seems to work. Haven't tested for performance. Your performance issue above seems to be hardware related?? Any concerns? -steve > > Steve Shorter wrote: >> Howdy! >> >> I am setting up virtual guests to have a LVM created >> from the host. It would be good to use LVM's in the >> guest also.. for easy volume expansion etc... >> >> ie. I am creating pv's/vg's/lvms on top of LVM's. It *seems* to >> work but some of the userland tools need the option -ff >> >> Does anybody see any issues doing this? >> >> thanx - steve >> >> _______________________________________________ >> linux-lvm mailing list >> linux-lvm@redhat.com >> https://www.redhat.com/mailman/listinfo/linux-lvm >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ >> >> > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/