We compared the I/O performance of vSphere 6.0 U2 over 16Gb and 32Gb Emulex FC HBAs connected via a Brocade G620 FC switch to an EMC VNX7500 storage array.

Iometer, a common microbenchmark, was used to generate the workload for various block sizes. For single-VM experiments, we measured sequential read and sequential write throughput. For multi-VM experiments, we measured random read IOPS and throughput.

Our experiments showed that vSphere 6 can achieve near line rate with 32Gb FC.

For details, please see the whitepaper Storage I/O Performance on VMware vSphere 6.0 U2 over 32 Gigabit Fibre Channel.