tcler's blog --- 其实我是一个程序员
Show me your flowcharts and conceal your tables, and I shall continue to be mystified. Show me your tables, and I won’t usually need your flowcharts; they’ll be obvious.

convert vmdk image to qcow2

convert

qemu-img convert -p -f vmdk -O qcow2 ./RHCE90.vmdk  /path/to/RHCE90.qcow2

shrink qcow2 image

#qemu-img convert -c -O qcow2 /path/to/RHCE90.qcow2 /path/to/shrunk-RHCE90.qcow2
virt-sparsify --tmp ~/tmp -v -x ~/VMs/RHCE/rhce90/RHCE90.qcow2 --compress shrunk-RHCE90.qcow2
  #^^^ virt-sparsify will call 'qemu-img convert -c ...' at the end