So I learned that since Red Hat 6 it is possible to choose between 3 algorithms for loadbalancing between different paths to my FC-SAN, the default dumb round-robin – and new – queue-length and service-time.
I have been searching for a long time now for a performance-comparison for different values for path_selector in a multibus-configuration, but I was not able to find any information based on real experience. I did not even find an assumption of what performs better in which situations.
Does anyone have done some real performance-testing on this question? Or information about resources I was not able to find?
Best Answer
I have a few servers that use queue-length and they haven't had any problems. In general, though, there's not much to optimize in terms of multipath. We still use basic round-robin for the vast majority of our servers -- it's a well-known setup with little unknown risk, and the performance upside for queue or service time based multipathing, at least in my shop, is small.
Do you have a specific problem you're trying to address? Or are you just making sure you're set up as well as possible?