What mean by stalled & how to solve it?

I have Susz Linux, Mylex Fibre Raid card, Trimm Tech eXtremeRaid 3000 external raid box, 8 Seagate Fibre hard drive.

When I tried to copy 2 GB data from the raid box to itself ( different directory ), I saw the copy going and going, then “stalled” for a while, start copy again, … a few times. So it took a long time to finish.

By the way, even it “stalled” when there is one hard drive instead of 8.

Any suggestions?

Thanks