NVME SSDs not performing as expected in ESXi 6.0 with the in-box NVME device driver
NVME SSDs are the follow-on technology to high performance PCIe SSDs. NVME SSDs solve the one irritant that PCIe SSDs had, in that PCIe SSDs needed a vendor specific device driver installed in VMware. With the new NVME SSDs and starting in ESXi 6.0, the in-box VMWare driver can be used with NVME SSDs from Tier-1 SSD OEMs. A custom vendor specific driver is not needed.
To get the best performance from a NVME SSD it should be inserted in a NVME / PCIe Gen III slot. A NVME SSD in a PCIe Gen I or Gen II slot will not be as high performing.
As an example – A P3700 Intel NVME SSD from 2014 installed in a PCIe Gen III slot does 700K Transactions Per Minute for a TPCC test (33 Warehouses, 500 users). The same SSD in a Gen I PCIe slot (on say a Dell 2950) does 200K TPM.
Also, when running TPCC tests using NVME SSDs, to achieve the maximum 700K TPM, you will also need adequate RAM and cores assigned to the VM. If you assign 16GB RAM and 16 cores to a VM while running TPCC tests, you should be able to get the max 700K TPM from that VM. NVME SSDs are so high performing that the bottleneck shifts from storage IO to either server RAM or CPU.