So I outgrow my Time Machine disk. I listen to the advice (repeated in multiple places) that one can simply use Disk Utility's Restore tab, select the old time machine disk as source and the new one as destination, and click restore to copy block-by-block, then rename the disk.
This works very well. I have indeed been able to use Time Machine on the new disk without losing any of the history.
But now I am in trouble. I am also outgrowing my MacBook disk. I put a larger disk in and install Snow Leopard from scratch. Now Migration Assistant does not recognize the new Time Machine disk (perpetually spinning wheel). Renaming the disk to the old name does not help. M.A. does recognize the old Time Machine disk, but that means manually managing the changes (and giving up on the larger TM disk). I reinstall Snow Leopard and do not miss that time the option to restore from Time Machine, but it still does not see the new Time Machine disk.
How does one convince Migration Assistant to use a Time Machine disk that duly has Backups.backupdb as a root folder and where "ignore ownership on this volume" is not set?