Disk Bottleneck Issues with MySQL

Looks like you have a lot of writes going on there. Look at the wkB/sec! Massive. Almost no reads at all.

Why so many writes? Have you got a lot of small updates and inserts going on? Have you split the transaction log from the data files, preferably on a different disk?

Also, put that slow performance logging on a separate disk. In fact, try to turn it off. It can have a performance penalty in its own right!

If you want best bang for buck, and you want RAID, it's normally recommended to use RAID 10 (or otherwise known as RAID 1+0). Basically it stripes the data, and then mirrors those stripes. It's the most reliable option.

Whatever you do, do NOT use RAID 5, it's just overhead and you telly gain very little in a disk crash due to often lengthy rebuild times.

Good luck!