Howto extend lvm for a KVM guest

Howto Resize  KVM lvm guest image

Here is how you add 5 GB of disk space to your guest:

1a.  # qemu-img create -f raw temp.img 5G

2.a # cat oldimage.img temp.img > newdiskimage.img

Sometimes you don’t have enough space to create a complete new image. If thats the case you can use this

1.b #qemu-img create -f raw temp.raw 5G

2.b #cat temp.raw >>  oldimage.img

3. After createing the new disk image you can start your VM and login

4. Delete the old lvm partition with fdisk (the one in the VM!).

#  fdisk -l to see partition

# fdisk /dev/vda

# Delete lvm (this is the partition with the type 8e)

# Create new one which starts at the same cylinder as the one you deleted (type 8e)

5. reboot the guest

# init 6

6.  Now after rebooting and logging in to the VM you can do a

# fdisk -l

and you’ll see the new space you’ve just added to the disk. So lets extend the physical volume, volume group and logical volume (named bla):

# pvresize /dev/vda2

#lvresize /dev/Volgroup/bla -L +5G

#resize2fs /dev/Volgroup/bla

7. If everything went well you should see the new diskspace with the command

# df -h

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