This afternoon I mostly migrated Xen guests from their old host to their new. (As part of a an upgrade of facilities. Upgrading in place would have been much fiddlier and more annoying!)
The migration took almost three hours, which was longer than anticipated but shorter than I'd feared. In the future I'll know to do it differently, but I managed to script it fairly well after the first couple were done manually.
Everything appears to be working correctly so I will soon nip out for some high quality beer.