I'm used to using RAID 10 almost always for DB setups. But I think that RAID 5 will gain significance once again when SSD disks begin to be more widely used for DB.

There are several reasons to prefer RAID 5 in such setups:

- SSDs are generally fast enough, even on writes, to compensate for the parity

- SSDs are expensive per GB (currently - around $2/GB for MLC) and having more usable GB is good

Currently I'm considering how to advice a customer for their new DB server and I'm debating with myself :w00t: whether to advocate for RAID 5 or even 6.

It will be most interesting for me to see the opinion of the other members on this.