I am doing a small testing and I don't know if my expectation is correct or not. Pardon me if I am ignorant. 

I created a VM and the VM is running. In the hypervisor I have created ".img" file and attached this .img file to the VM.

My expectation is that, if VM is writing files to the attached disk, then it should reflect in the .img file created in the hypervisor. But It is not working as my expectation. 

Please correct me if my expectation is wrong.

Steps:

1. Created disk.img in the hypervisor using the command: dd if=/dev/zero of=disk.img bs=1M count=50; mkfs ext3 -F disk.img

2. Attached the disk to the running VM using the command: virsh attach-disk <Domain-Name> --source disk.img  --target vdb --live

3. In the VM, I mounted the disk and created few files.

4. In the hypervisor, I mounted the disk.img to check if the file created in the VM exists in the .img file.

   >> I am not able to see those files.