If you used the via82cxxx in edgy, then your drives were hda2 and hdb2, right?
More than likely you need to tell mdadm that you are using sda and sdb now. Check /etc/mdadm/mdadm.conf.
I suggest instead of device names, you use the UUID symlinks in /dev/disk/by-uuid/, so instead of /dev/sdb, you would use /dev/disk/by-uuid/XXXXXXXX-part2, for instance.
If you used the via82cxxx in edgy, then your drives were hda2 and hdb2, right?
More than likely you need to tell mdadm that you are using sda and sdb now. Check /etc/mdadm/ mdadm.conf.
I suggest instead of device names, you use the UUID symlinks in /dev/disk/by-uuid/, so instead of /dev/sdb, you would use /dev/disk/ by-uuid/ XXXXXXXX- part2, for instance.