Dave,
Luke,
Have you tried the areca cards, they are slightly faster yet.
No, I've been curious since I read an earlier posting here. I've had a lot more experience with the 3Ware cards, mostly good, and they've been doing a lot of volume with Rackable/Yahoo which gives me some more confidence.
The new 3Ware 9550SX cards use a PowerPC for checksumming, so their write performance is now up to par with the best cards I believe. We find that you still need to set Linux readahead to at least 8MB (blockdev --setra) to get maximum read performance on them, is that your experience with the Arecas? We get about 260MB/s read on 8 drives in RAID5 without the readahead tuning and about 400MB/s with it.
- Luke