Our external Sybase database does some sort of soft crash once a week where no notification is brought to our attention except for the entire school district being unable to log in.

Users not being able to log in is the first symptom, the second is the VMWare CPU graphs for the guest flatline. A third symptom is the ZCC become unavailable as Page Not Found.

Sybase will continue to show as up and running but if I stop, then start sybase-asa it starts right back up and users can log in again.

Where can I find logs to show what is going on?

SLES 10.2.2: 3 Primary Servers, 1 External Sybase server (no ZCM)
Windows 2003: Satellite imaging server
VMWare 3.5.0 environment