If I get an alert that the C Drive is full on a particular node how can I show what ESX Host it is on from the email variable? SAM shows this in the web console but does not seem to have the option within the variable listing.
If its NPM and Node Summary View that you are talking about the details are picked from the below mentioned tables:
Nodes->VIM Virtual Machines->VIM hosts.
And if you are using Volumes type monitor to alert on C drive on your advanced alert manager you will not find the details (ESX Host) you require.
Probably this can be achieved by a Custom SQL Alert but then I have never tried it myself