We had a 180GB VM image. Inside the guest VM everything is OK and hdd size is 180G. but when we look the image size on the host it is 475MB. I am afraid that if we restart, the VM wouldn't work. I checked the size by
ls -sh 457M x.img
qemu-img info x.img file format: raw virtual size: 456M (478309888 bytes) disk size: 456M
this is the this configuration :
<disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/vm/x.img'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </disk>
and the disk cache setting is default.
both host and VM are ubuntu 12.04