As the others mention, read performance is bad while in a degraded state. However, seeing as they're running their log on the same drives, they have quite a lot

As the others mention, read performance is bad while in a degraded state. However, seeing as they're running their log on the same drives, they have quite a lot of write ops as well. RAID5 is notoriously bad for write performance, just as RAID6 is. This is a classic writeup on why you should avoid RAID5 at all costs for a scenario like this: http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt