how to determine if MD3200i is overloaded based on IOPS ?

Hello everyone,

I need your help and advise, I did some searches but didn't find an answer..

I have MD3200i with 12 15k SAS drives (600 GB) configured as RAID 10.

I am running out of space and I want to know if I should change to RAID 5 or 6.

or just buy MD1200 to expand.

so I started by looking at the IOPS figures from the monitoring manager for MD3200i.

based on my situation the maximum IOPS will be  = 12 (# disks) *180 (IOPS for 15k SAS)  = 2160

from the IOPS table view , I see max IOPS. current IOPS, but there is no average IOPS.

so I am wondering how can I determine if my current MD3200i is reaching its limit
 or if I can still add more load to it ?

I am guessing an AVG IOPS will help me ..but not the Max IOPS ..right ?

 see the  screenshot for monitoring table below

Thanks