A healthy 8GB fabric will do just fine. 16GB is faster (obviously) and overall more efficient but I've seen very heavy workloads do just fine on 8GB (and 4GB for that matter).
Here is how the MSA defines a "tier"
- Performance=SSD
- Standard=15k or 10k
- Archive=7.2k
You can't change this. Therefore; 10 and 15k drives, in the same pool, will been seen as the same tier. IO's will therefore have the potential to perform at the lowest common denominator. In this case 10k. Also, if you have different RAID types or set sizes in the same tier (within a pool) then IOs would porentially operate at that lowest common denominator as well.
We'd really need to dig into your "workload" more. How are sure that the workload is identical between your environments? What's your percentage of read/write? Block size? etc?
Can you supply me with some performance info? Like outputs from:
- show controller-statistics
- show host-port-statistics
- show disk-group-statistics
- show disk-statistics
Also, if you haven't already, you may want to open a support case.
Thanks.