dean gaudet wrote:

one theory was that i lucked out and the pending sectors in the unused 
disk near the md superblock... but since that's in general only about 90KB 
of disk i was kind of skeptical.  it's certainly possible, but seems 
unlikely.

I can discount this one in my case, as sectors were being repaired 
progressively across the disk, as can be seen in the smartd reports.

You can't have too many checks is the moral of the story I guess.

Regards,

Richard