On 21/04/2015 03:25, Wen Congyang wrote: >> > Please do not introduce "<name>+colo" block drivers. This approach is >> > invasive and makes block replication specific to only a few block >> > drivers, e.g. NBD or qcow2. > NBD is used to connect to secondary qemu, so it must be used. But the primary > qemu uses quorum, so the primary disk can be any format. > The secondary disk is nbd target, and it can also be any format. The cache > disk(active disk/hidden disk) is an empty disk, and it is created before run > COLO. The cache disk format is qcow2 now. In theory, it can be ant format > which > supports backing file. But the driver should be updated to support colo mode. > > > A cleaner approach is a QMP command or -drive options that work for any > > BlockDriverState. > > OK, I will add a new drive option to avoid use "<name>+colo".
Actually I liked the "foo+colo" names. These are just internal details of the implementations and the primary/secondary disks actually can be any format. Stefan, what was your worry with the +colo block drivers? Paolo
