I've got three C240 servers each with two SSDs and four spinning disks that are connected by 10gig over the Cisco VIC. The problem is that vSAN requires raw access to the drives so that it can lay its own RAID on top. However I cannot seem to find a way to get the LSI MegaRAID SAS 9266-8i card to do that.
Cisco supplied firmware for LSI MegaRAID adapters do not support passthrough SAS HBA mode. Your only option is to make invidual RAID devices of each disk, but by doing this VMware VSAN cannot recognize disk geometry so it cannot optimize data placement on spinning disks.
I had SR open for feature enhancement about this but I woulnd't hold my breath while waiting for fix.