[CentOS-virt] Resizing disks for VMs

Mon Sep 28 20:09:57 UTC 2009
Dennis J. <dennisml at conversis.de>

On 09/28/2009 06:37 PM, Fabian Arrotin wrote:
> Dennis J. wrote:
>> Hi,
>> Is there a way to make a PV xen guest aware of a size change of the host
>> disk? In my case I'm talking about a Centos 5.3 host using logical volumes
>> as storage for the guests and the guests running Centos 5.3 and LVM too.
>> What I'm trying to accomplish is to resize the logical volume for the guest
>> by adding a few gigs and then make the guest see this change without
>> requiring a reboot. Is this possible maybe using some kind of bus rescan in
>> the guest?
> No, it's not possible unfortunately. On a traditionnal SCSI bus you can
> rescan the whole bus to see newer/added devices or just the device to
> see newer size, but not on a Xen domU .
> At least that's what i found when i blogged about that . See that thread
> on the Xen list :
> http://lists.xensource.com/archives/html/xen-users/2008-04/msg00246.html
> So what i do since then is to use lvm in the domU as well and add a new
> xvd block device to the domU (aka a new LV on the dom0) and then the
> traditionnal pvcreate/vgextend/lvextend. Working correctly for all my
> domU's ..

I just tested this and it works great, thanks!