"... so, I thought, why not?"

I set up a RAID 6 volume using eight 400GB Seagate drives. The array was fully initialized, and partly loaded with data.

When I added two more drives to the set, and monitored progress for a couple of days, I determined that the array would require nearly 3 weeks (!!!) to complete the expansion, even if I let it happen in BIOS, so that the volume wasn't being used by Windows.

I moved the data off of the volume, thinking that an expansion of an empty array would be faster; but, it didn't appear to help. In the end, I completely wiped and recreated the volume, which only took a few hours to initialize.

Is this "normal" performance?

I can't see how these cards can be considered for enterprise level usage if it takes nearly a month to add a TB to a volume. Some of today's start-ups don't even last that long :-)

All of the drives are jumpered to enable 3.0gbs transfer (SATA2), and the read and write caches are both enabled on the card, despite the current lack of a backup battery.