Your customer has been a long time Avamar Virtual Environment (AVE) customer. They have older AVE installations along with newer installations. They notice that older configurations are not receiving the same performance as the newer configurations.
The customer points out that both configurations have fairly high I/O requirements but use different disk pools. They understand performance is affected by RAID levels and would like your recommendation.
Based on best practice, which RAID level is recommended for virtual machines with high disk usage?