I am using ubuntu 12.04 and have seen this: https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/1025244
Our qcow2 images are growing far beyond what they should... with some of them growing to as much as 600gb when they should have only 20-30gb
Others are growing more slowly but still growing... normally cow images that should have a maximum of 10Gb are now showing 20gb+ this is insane! What i mean by growing is that their virtual size should be 10gb max yet they grow far beyond that on the qcow2 file
We are thin-provisioning the disks with qemu-img
I know i can temporarily solve this by reclaiming unused space with virt-sparsify.
We will soon have a big problem when the images are too big that i can't virt-sparsify them anymore to get the space back (since double the size is needed for the temporary copy)
We do have snapshots on the machines...
My questions are:
- Does this ONLY happen because they are thin provisioned?
- If I preallocate them will this go away?
- How can I avoid this? changing to raw? preallocating?
- Any way I can reclaim that space without needing double the space?