I love me some RAID5. When setup properly, I haven't run into any problems with performance or reliability over RAID1 or RAID1+0. Obviously that means having enough cache to front end the writes. I still meet people, especially EMC people, who are so in love with the performance gain of RAID1 that they ignore the fact that they aren't pushing enough IO to stress RAID5. Anyway, what do you usually push for when implementing a new array? If a DBA came up and demanded RAID1 because that is fastest, would you just agree or would you argue for RAID5? Have you looked at RAID6? If your array supports it, would you rather use RAID6 instead of RAID5 to increase your data redundancy?