Shrink qemu qcow2 files
Excerpt from source:
Windows Guest
1.Delete all unnecessary files, empty recycle bin
2.Defragment drive (you might need to do this several times, until you see it “compacted” well)
3.Use sdelete to zero free disk space. Please note that this operation
will cause that all drive free space will be filled by zero, so the
virtual machine image will grow to the maximum size.
Using command prompt
sdelete -c c:
Linux/FreeBSD Guest
# dd if=/dev/zero of=./zero bs=1M
# sync
# rm -f ./zero
Note, the bs parameter is important, since it greatly reduce time necessary to complete this task.
Host
Convert image to the same format that is currently is (e.g. qcow2 =>
qcow2)… during this procedure it will release unused space.
# qemu-img convert -O qcow2 w2k3.qcow2 w2k3-shrinked.qcow2
Source:
http://mindref.blogspot.com/2011/07/shrink-qcow2.html
Download sdelete from here:
https://technet.microsoft.com/en-us/sysinternals/bb897443.aspx
