Detect if ESXi installed on internal SD flash

HI All,

im currently working on a project to free up the disks on the physical hosts by moving the hypervisor over to Dual internal SD cards.  Does anyone know of a way to detect whether ESXi has already been installed to an SD rather than to the disk arrays?  I can't seem to find the information in vCenter.  Maybe there's a command in the CLI?

thanks!

Jon