virsh command

http://www.cnblogs.com/chenjiahe/category/845519.html

resize

qemu-img resize win2k8r2.qcow2 40G

convert

qemu-img convert -f qcow2 -O raw
qemu-img convert -f {source-format} -O {output-format} {source-filename} {output-filename}
qemu-img convert -f qcow2 -O raw precise-cloudimg.img precise-cloudimg.raw
qemu-img convert -p -c -O qcow2 Windows2008R2-Standard  Windows2008R2-Standard.qcow2  压缩