arobarKaseya will tell you that running a secondary K server violates you license, so take that for what it's worth.
We use the primary/secondary to point to different WAN links that both run into our network. If the primary ISP drops for any reason, the agents are still checking in. We use IPs for both, not DNS names. We monitor DNS resolution separately.
pdxkid is correct, the RC functions do not work when agents are checking into a secondary server address. This includes control, FTP and chat in our experience so far.
ljgrizzleOur original setup was to for the Kaseya check-in servers was 'DNS.1STHOST.COM' and secondary being 'IP.ADDRESS.HERE.93'. Swapping the two around, all clients took the update, nothing skipped a beat, however this also resolved the ability of Remote Control. A flaw with Kaseya? Please respond!