Hello All!

We are in the process of reconfiguring our SSD backed CX4-120  (single shelf with 15 disks) and we ran across the following note in the EMC Clariion Best Practices for Performance and Availability regarding dual drive ownership. (screenshot because this PDF must not allow copy/paste).

http://www.emc.com/collateral/hardware/white-papers/h5773-clariion-best-practices-performance-availability-wp.pdf

The key points for me are:

• Drives are dual ported and can accept IO from both SP's at the same time.
• Dual ownership may result in less predictable drive behavior (higher response time) than single ownership because of deeper drive queue lengths.
• Single SP ownership of a drive is preferred
• I am assuming all of the above points are valid in the context of SSD as well.

The catch for us is that we are not adding another shelf of disks and creating a second raid group.  That would make things very easy.  Instead, we are considering carving the existing 15 disk shelf (SSD) into two Raid Groups rather than creating a single 15 disk Raid Group.   That will cut the total IOPs/throughput available to a single SP/Raid Group in half but the total available throughput will be the same.  (all LUNs belonging to a Raid Group would be owned by one SP)  

We tried the single 15 disk raid group, werent completely satisfied with the performance and then came across the Clariion Performance and Availability Guide.  That is why we are now considering two raid groups instead of one.

In this particular scenario, would carving up the SSD disks  into two separate Raid Groups make any difference one way or another?  

Thanks!