Hi

First of all, who said that on RAID 5 i/o doesn't matter.

Use RAID 5 only when u have high reads e.g. for LDAP.

If u want to keep a database keep it on RAID (1+0)

Change the RAID if u can or u will be going to be in trouble....

U can ask any good consultant what they have to say about RAID 5

Regards
Amar