World Of Warcraft: If Your Server Keeps Crashing ...

Nethaera has something to say about it.

We are aware that certain realms are experiencing performance issues such as continent crashes, "world server down" errors, and instance crashes, primarily during peak hours. We're monitoring these realms very closely and have already applied various fixes, and additional fixes are being tested as we speak. As always, we appreciate your patience and support with these issues; we'll continue to provide updates as more information becomes available.

This is happening a lot on my server, I hope it gets fixed soon. :(