Has anyone experimented with iSCSI round-robin multipath policy changes besides switching the value to 1 IOP instead of the default of 1000?
Pretty much all of what I've read suggests just using 1 IOP. While this results in a 1:1 balance across two NIC paths, is there any reason to consider a different value?
While 1000 seems too high for some reason (which is why people change it), is 1 too low? Is there perhaps some performance advantage to a value of 100 or 200? I can't specificly say why, but it seems reasonable to believe that there may be some reason to not invoke RR until a higher threshold has been reached, but lower than the default of 1000.
Has anyone experimented and seen any difference? I did some basic benchmarks with an Equallogic PS4000 and frankly didn't see any difference between 1000 and 1 but I do see the NIC workloads evened out at 1.
And is there some rationale for 1000 being the default? I can see some basic math of 1k average payloads * 1000 IOPS equalling roughly 1 Gbit/sec and thus an "overflow" threshold for a single NIC.
It'd sure be easier if the RR policy was settable in the GUI, too, but maybe like jumbo frames and RR itself it will be in a future version.