vSAN SSD 'Permanent Disk Failure' on Micron P420M PCIe 700G disk

I am having problem on our vSAN environment ( setup on 4 brand new Dell PowerEdge R820 ESXi 6.0 server ), The hardware is same as https://partnerweb.vmware.com/programs/vsan/Virtual%20SAN%20Ready%20Nodes.pdf suggested:

700GB P420M MLC PCIe Solid State Storage Card-Assumes System * 2

1.2TB 10K RPM SAS 6Gbps 2.5in Hot-plug Hard Drive * 12

It's working fine for several month, but all a sudden it shows a error 'Permanent Disk Failure' on one P420M SSD disk and the whole diskgroup is down.

I opened Vmware support ticket, they suggested it could be the hardware failure on the SSD disk or firmware, but we just bought it for only a few months.

I am wondering where I can confirm the P420M SSD disk 's status/firmware version? iDrac doesn't show any information about the SSD PCIe devices.

I tried a Micron tool RealSSD Manager (RSSDM), it's installed/running ok on the ESXi6, but couldn't detect any device.

Maybe this is not the right place to ask this question, anybody can suggest where I can find the right place to ask questions about Dell vSAN hardware?

Thanks,

-Jack