script to check tarchive disk silos

[cchou]

This issue needs more research, but since disk-fixity takes at least 2 weeks to cycle through all disk silos on tarchive, it would be useful to have a script that runs daily that checks that all expected disk silos on tarchive are present and not empty.

Eventually it would be useful to incorporate this sort of check each time a silo GUI is accessed, to alert an Operator of a problem.

Use case: accidental unmounting of a disk silo (if done by most Sys admins xymon alerts would be turned off before unmounting).

--Lydia