I would like to know how i can be warned if a san disk is unconnected.

I have a server which have 2 category of san disk, the following disks H/I/J/K/L/M (theses disks are from EVA1) and the following disks V/W/X/Y/Z (theses disks are from EVA2).

I wanted to know if one of the disks of the part 1 is disconnected and send an email then i wanted to do the same with the disks of the part 2.

What is the best way? ??
WMI and test a value range of the capacity of the disk ???

Any idea ....

Jean