I have asked other, more pointed questions, around this general topic that lead me to where I am with this question. Sorry for the bad subject but that just about sums it up.
I have been working toward why we see poor performance within a 4.0.0 ESX cluster with 8 nodes all connected to an Equallogic iscsi SAN with four members. Here are some performance highlights.
san avg read latency: 12 ms
san avg write latency: < 1 ms
san avg iops 2200
esx physical device read latency: 20-30 ms
Here's what I see in read/writes from guest depending on the underlying disk:
Initiator in guest OS
read: 45 MB/s
write: 223 MB/s
RDM/VMDK
read: 17.9 MB/s
write: 118 MB/s
I am concerned about the large difference in the guest initiator vs. RDM/VMDK and the fact that my read performance lags so far behind. I already have a gap where round robin path selection is not being used but not convinced that would cause this. Have any hints to where I should start focusing my attention?
