ArunKKR,
Sorry my later answers but initially thanks a lot for the comments.
The issue is this solution was originally created with a single DG where "space" requirements does not allows me to break it into at least two DGs, based on volumes and space requirements.
For example, if I divide this in 2 Disk Groups, I would not have a single Volume larger than the size of half of these disks, or around 6,5TB. One issue is that I have on thi solution a backup partition of 7TB or larger, even pretty close, to a volume to be created in a single DG. So I would not be able to create, or distribute I/Os anyway, since backup will not be always in use. Based on sizing, and avoid to have one more parity disk, decide to let a single DG, since we cannot easily arrange more disks right now.
I see your point and make sense. I did not expect to reduce this much in sequential write. My expectation, having more disks than on the HPE tests, was that limit would be in the FC port speed, of course reducend by around 30% or a little more. This would match the around 4.3Gbps/4, or around 1Gbps per 4DG/2Pool all 4 ports used with a server.
But I got your idea where probably without SSD and witn the originally dimension we will need to use the around 550MBs throughput we see on tests. Of course OS cache also increases this speed if not writting all the time into storage.
Thanks a lot for the clarification and where we can improve in this particular configuration with a single DG.