I have subsribed to a service that will monitor the server and send me a text message if the site is down, or gets one of those DB errors that happened for a few minutes last week.
I signed up for a premium service that checks every two minutes (rather than free services that check every 30 to 60 minutes, or cheaper ones that check every 5-15 minutes), and it will alert me if it gets two failures in a row (to eliminate some false positives).
So, if the server goes down or starts returning DB errors (the databased crashes), I should have a text message/page within 4-5 minutes of it being down.
Also, here is a link to a page that will show the server uptime/downtime stats:
http://www.siteuptime.com/prem_stati...&&UserId=78430