[Fedora-xen] Xen to KVM Migration - How to resize LVM Partisions using KVM

[Dale Bewley]

On Sat, 2009-02-28 at 14:23 +0000, MOHAMMAD MATEEN ASLAM wrote:
>  Hi, I am migrating from Xen to KVM. I have created a VM which is
> based on LVM (/dev/VolGroupV00/vm). I have installed FC-10 on VM with
> swap, / and /var partisions.
> 
> Now i want to resize my / and /var partisions. I have resized LVM
> (/dev/VolGroupV00/vm), how to resize inner partisions (/, /var) of
> LVM ?
> 
> Can anyone guide me how KVM deals with LVM and how to manage resizing
> in a painless way.

Apparently you are not using LVM inside the guest. I would do so for
flexibility.

If you want to resize the guest partitions from the host, you can make
your guest's "hard drive" available in the host by using kpartx. You can
then manipulate this device to resize the partitions on it.

'kpartx -av /dev/VolGroupV00/vm' will create /dev/mapper/VolGroupV00-vm.
Resize it as you would any disk (see parted, resize2fs) then remove the
device mapping with 'kpartx -dv /dev/VolGroupV00/vm' when done.

See
http://fedoraproject.org/wiki/Getting_started_with_virtualization#Accessing_data_on_guest_disk_images
And I have some tangentially related but not directly applicable notes
at http://tofu.org/drupal/node/55 http://tofu.org/drupal/node/60

Hopefully that was at least marginally helpful.