Oops, I mixed up blkid and vol_id. Please try running vol_id /dev/sda and see if it identifies it as a raid member. Last I checked, vol_id has bits of the signature detection code hacked out of dmraid built into it so it recognizes the disk device as a whole as being a raid member and exports that info to udev, but then udev ends up running vol_id on the individual partitions, which happily identifies them as normal, usable partitions, and this is not the case.
Once vol_id identifies the entire disk as a raid member, the partitions on it should be ignored...
Oops, I mixed up blkid and vol_id. Please try running vol_id /dev/sda and see if it identifies it as a raid member. Last I checked, vol_id has bits of the signature detection code hacked out of dmraid built into it so it recognizes the disk device as a whole as being a raid member and exports that info to udev, but then udev ends up running vol_id on the individual partitions, which happily identifies them as normal, usable partitions, and this is not the case.
Once vol_id identifies the entire disk as a raid member, the partitions on it should be ignored...