Re: Re: Re: [Xen-users] how to expand disk inside of domU?

[Matej Zary <zary@xxxxxxxxx>]

On Tue, 2010-04-27 at 00:04 +0200, Matej Zary wrote:
> On Mon, 2010-04-26 at 15:36 -0500, Dan Waterloo wrote:
> > i'm trying to find a way to expand a selected partition in my
> DomU...
> >
> > when in a console in the domU, here are the disks available:
> >
> > [root@localhost ~]# df -h
> > Filesystem            Size  Used Avail Use% Mounted on
> > /dev/mapper/VolGroup00-LogVol00
> >                        13G  3.5G  8.1G  30% /
> > /dev/xvda1             99M   21M   74M  22% /boot
> > tmpfs                 257M     0  257M   0% /dev/shm
> >
> > I'd like to expand the /dev/mapper/VolGroup00-LogVol00 disk to 25G
> >
> > The domU is based on an image file, 'webs.img' that resides on a
> disk
> > in the Dom0.
> > In the dom0, I add space to the webs.img file with the following
> > command:
> > dd if=/dev/zero bs=1024k count=12288 >> webs.img
> >
> > then, when i create the webs domu, i.e. xm create webs;
> > it starts, and the new space shows up as "unintialized' space 
> > in the domu. (I see this using vnc to reach the desktop, and
> > open the LVM tool to see the new space).
> >
> > The problem that I'm having is to 'attach' the unintialized space in
> the
> > domU to the /dev/mapper/VolGroup00-LogVol00 disk, and then to expand
> the
> > LogVol00 disk to take advantage of the space.
> >
> > I'm running Centos5 on the dom0, and in the domU. Xen is version 3.
> >
> > Any suggestions? if so, can you please be explicit as to _where_ to
> run the various
> > commands, in the Dom0 or DomU? At this point, I'm pretty confused
> about
> > what to do where....
> >
> > Thanks!
> >
> 
> So to sum it up - your DomU hdd is file based. This virtual disk is
> "LVMed" in the DomU. You resized the virtual disk in the Dom0 and now
> want to utilize this space into the domu using the LVM.
> 
> My guess is, you need to allocate the non-utilized new space to the
> main
> LVM volume group. This volume group is made of actual physical
> volumes.
> So this point me to pvresize, which can be used to extend existing
> physical volume after extending the partition via fdisk.
> 
> LVMs inside DomU can be pain in the *** sometimes, but it should be
> just
> few more commands.
> 
> Rough walk-thru (smaller steps are missing - man and google are good
> friends):
> 
> 0. back up your data
> 01. back up your data
> 02. well, do it, really!
> 1. shut down DomU
> 2. mount the virtual disk img file in the Dom0
> 3. expand the partition with fdisk
> 4. expand the physical volume with pvresize


4.5 ensure that volume group expanded too (vgscan?)
4.6 expand the logical volume with lvresize
 
> 5. expand the filesystem with apropriate command for your filesystem
> (e.g. resize2fs)
> 
> another solution could be using liveCD with some linux distribution
> with
> LVM tools and boot it from virtual cdrom (iso image) in hvm VM setting
> and do these steps "inside" the DomU.
> 
> 
> Someone correct me please if this is dumb solution. :)
> 
> Regards
> 
> matej
> 
> 

forgot few things...

Matej

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