I'm am in the process of provisioning a new ESX 6.5 host based on a DALCO S2600WT2R server (basically a custom package based on an Intel server board S2600WT2R).
We are using hardware RAID (card MegaRAID SAS Fusion Controller) and the virtual disks created by the hardware are not seen as SSD (which I guess is to be expected ?).
I have followed this procedure (which I have done a few times under v5.5 and 6 without issues) and although it did not report any error message the affected disks are not anymore seen by the host server 
They don't appear at all in the vSphere client (yes still using it !) and as "degraded" in WebUI:
Nothing obvious (to me at last) reported in syslog.
Any idea ?
(and yes I understand that there is now a GUI for that I that I should have presumably used it).