It appears that the SSD disk in B-230 Blades show up as non-ssd in esxi5.
If you want to use this as Host Cache you have to change the disk via cli following the following procedure :
First get the naa for the disk from the Gui.
the ssh to the box and run the following cli:
esxcli storage nmp device list
esxcli storage nmp satp rule add -d " naa.60030130f0900000144427e80bd37b79" -s "VMW_SATP_LOCAL" -o "enable_ssd"
esxcli storage core claimrule load
esxcli storage core claimrule run
esxcli storage core device list -d naa.60030130f0900000144427e80bd37b79
REBOOT ESX
Enable Host Cache
