KVM Gotchas

Common useful commands for KVM Guests

LVM error fixes:

• not exclusive for KVM, but since I have so many of these VM's thats where I see it a lot.
• commonly happens when do-release-upgrade is run, or when some updates happen to the lvm code. My GUESS is that the metadata contains the lvm version in there somewhere and does not get updated.
• This fix is only for the metadata

  WARNING: PV /dev/sda5 in VG dns01-vg is using an old PV header, modify the VG to update.

Fix:

vgck --updatemetadata dns01-vg
vgck --updatemetadata <VG Name from warning message>

Create new Image

qemu-img create -f qcow2 -o preallocation=metadata FILENAME.qcow2 XXXG