I am currently using backing file.The question of my concern is regarding the I/O operation Now when we create a external snapshot in qcow2, a new file is created leaving the original file as backing file Can any one tell,how the I/O is performed in detail way?.
Means when the new snapshot is booted which refer to the backing file as original file. How read operation is performed? how it is decided whether the file is present in the snapshot image or the backing file.?
when write operation is performed how it is decided whether the file is already present in backing file or we have to create a new one ?