[jonnzus]

I have been running 4 or 5 server in same (xen) vps without problems.
Atm I'm running 2 hlds server, apache2 and ts3 without any problems
You just have to bind your hlds server to different ports.

[DrunkenKoZ]

I have to say that OpenVZ is indeed a nightmare when it comes to game server hosting. If you find a decent XenVPS provider then you can guarantee stable servers with no lag. My last XenVPS was a single core, 1GB of ram, and I had 3 servers up and running on it with no lag. I had a Garry's Mod Server and 2 cs 1.6 servers running on it. The Garry's Mod server was constantly 32/32 and the cs 1.6 servers averaged 10-15 players a day at random times.