Hi Paolo, Why the data changed is because the block device is used for a cache device in each host. So, after migration, such block device will be changed, but I still want this vm can access the data in the new block device.
Thanks On Tue, Jun 24, 2014 at 4:25 PM, Paolo Bonzini <pbonz...@redhat.com> wrote: > Il 24/06/2014 21:55, Xiongzi Ge ha scritto: > > Hi Paolo, >> >> I am trying to do migration with two different block devices in the >> source and destination hosts. For example, in the source the data in >> /dev/vda are 'aaaaa'. The guest has a cache. These data are cached. In >> the other host, the data in this device are 'bbbbb'. >> > > Again, what you are doing is invalid. The point of migration is to have > the same thing running on the source and destination, including disk data. > > > If we do migration, I want the guest vm recognize this change. >> > > This is not _what_ you want to do. This is _how_ you want to do it. > > (Example: you eat a big mac. _What_ you want to do is not being hungry. > _How_ you want to do it is going at McDonald's and grabbing a sandwich. > Similar to your migration example, there's probably a better way to > achieve your objective). > > So, why do you want data to change upon migration? > > > How does qemu deal with the cache data? Thanks. >> > > It's not QEMU that's caching data, it's the guest. There's nothing that > QEMU can do about it. > > Paolo >
