From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from glen-mhor.englab.brq.redhat.com (glen-mhor.englab.brq.redhat.com [10.34.32.149]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n55800a5000831 for ; Fri, 5 Jun 2009 04:00:01 -0400 Message-ID: <4A28D080.3070804@redhat.com> Date: Fri, 05 Jun 2009 10:00:00 +0200 From: Marian Csontos MIME-Version: 1.0 Subject: Re: [linux-lvm] lvm on a single big partition or just a single big partition? References: <20090603164231.GA23418@m364d1.ece.northwestern.edu> <20090603184601.GA25936@m364d1.ece.northwestern.edu> In-Reply-To: <20090603184601.GA25936@m364d1.ece.northwestern.edu> Content-Transfer-Encoding: 7bit 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"; format="flowed" To: LVM general discussion and development Zhengquan Zhang wrote: > On Wed, Jun 03, 2009 at 02:42:29PM -0400, Stuart D. Gathman wrote: > >> On Wed, 3 Jun 2009, Zhengquan Zhang wrote: >> >> >>> For one harddrive I often create a /boot parition that is not lvm and >>> create a huge partition on the rest of the harddrive for PV of lvm. Now >>> I am thinking what is the difference between doing partition like this >>> and just a single big partition without lvm? >>> >> With LVM, you can create many logical volumes. If you only ever create one >> logical volume that fills the entire PV, and you aren't spanning drives >> (multiple PVs) or mirroring, then LVM is not doing anything for you. >> Not at the moment, but the moment you run out of space and decide to add another drive, it will save you a lot of trouble moving all your partitions around... > That is what I am doing, so I am not fully utilizing lvm. another > question, is it advisable to create on pv for one harddrive? > > Yes, it is the right way. Having 2 PVs on single drive offer no benefit I can think of, and actually it is a step back - you can not share "free space" between PVs, thus it is a way to simulate old fashioned partitions. >> Even with just one LV, leave some space for a snapshot. Then you can >> take more consistent backups by creating a snapshot of your main LV >> and backing that up instead. Put your swap space in LVM as well. >> > > Thanks for pointing out this. I never thought of leaving space for > snapshot. and the swap too, why it is good to put swap in lvm? > > I think most of installers do not think of it neither (unless you partition you disk yourself, which is not so difficult, but may be a bit scary for newbies) - I would like an install option "leave N% of created PV free and use only the rest now". >> One reason to create multiple LVs is for virtual machines. If you >> run Xen, VMWare, or other virtual machine, then each virtual machine >> should have its own LVs for disk drives. This is more efficient >> than using a filesystem file for a virtual disk. >> > > Oh really, I never thought about this, so virtual machine can directly > use lv for the as their filesystem? > > >> PS. I wonder if Grub will ever support LVM? Does LILO work with LVM? >> > > As I know, LILO does, buy anyway we've got separate /boot. > > Thanks a lot Stuart, it helped me a lot, > >