I have currently have some Compellents that are using RR as the path selection, as opposed to Fixed. I know it rotates through 1000 iops, but I am curious if using RR can cause any IO degradation as the host has to rotate the IO through all your paths(I have 8 active IO paths). I have tried to limit to 4 paths--but due to having to traverse through some old 4gbit switches and how they are layed out--my backup peak bandwidth could saturate the system if I lose an HBA.
I have seen my GAVG spike from 7 to 30 roughly, nothing sustained--yet. So am curious if rotating through 8 paths can introduce any latency rather than just shoving it down a fixed path.
Thanks for any comments!