What kind of hardware are you using as a server (hopefully not a 10+ year old desktop with a client OS)? I've seen multiple 'downtimes' this year.
Back Online
Detailed hardware specs are classified due to paranoia, but it's a fairly new machine purchased when the previous server failed. It's a mini PC with an I3 processor with 8 GB ram running Ubuntu 13.04 (previously 10.04).
The server that was running the site prior to the conversion to Drupal is now 10 years old, and is running Windows 2000 Server. Until recently, it was still up and running 24/7.
The current server was working off of a copied image from its defunct predecessor. I suspect that running an OS that was originally installed on a different machine was causing performance issues. Things seem significantly faster after the OS update.
Downtime is the price I pay for self-hosting. I'm on consumer-grade DSL using consumer-grade hardware. It's a one man operation. Failures that would be a non-issue in a commercially hosted environment can take the site out for days. But if it means I never have to get on the phone with tech support and have some guy ask questions about the site, then I'm fine with it. I don't think I'd have kept at this for so long had it been otherwise.
The site runs faster for me now :)