As has been said, it's a wonder that these things work at all, let alone as well as they generally do.
I was wondering whether, in having apparently been stuck on the Seagate as the cause of his problem, tacit was overlooking its enclosure, and your excellent explanation of "the process" suggests that the enclosure may, indeed, be a/the culprit.
On the other hand, though, the full extent of tacit's problem is unknown without his having run all tasks from/on all volumes; the drives/enclosures that haven't choked may not have been pushed to their limits with what they've been asked to do so far.
