Wasn't a DDoS attack, if it was then the entire dedicated server would become unresponsive (you can view the uptime/downtime in my signature or at
http://status.frostgaming.com)
Long story short, there was a huge exploit for the SA-MP server under the operating system we were on and I had to do a full migration in order to fix it. (I won't go into further details on the exploit even now that we're safe, it is still a big security risk to a lot of other server owners. I even tried the exploit on a grand larceny server on two different dedicated server locations and it crashed the entire server. I also doubt it would have been fixed any time soon, so I can't wait for that, neither can you guys.)
Sorry for any inconvenience caused.