Methods to reduce lag? VPS

I've been running a dedicated server on a (budget) VPS for a couple of weeks now. *Generally* it works very well and people have been using it achieving fairly good pings and some very good pings too.

Occasionally though, a huge lag spike will come along ruining play for a few seconds. It's only once every probably half hour, but it's annoying when it happens.

I might be SOL with a VPS that wasn't actually sold to me as a game server, but does anyone have some ideas on whether there is something that might be causing it? Or if there are any ways to attempt to reduce it happening so much?

I'd love to continue running the server, but there isn't much point if it's just gonna piss people off.

Running Warsow 1.0 i386 on Ubuntu 12.04.

Are you running anything else on that machine? backup cronjob perhaps?

Only the usual server things are running, like apache, sshd, xrdp (almost never use xrdp, so it just idles mostly). Running HTOP at least only shows wsw_server as using any actual CPU (4% most of the time). Memory usage is well within its means too. There isn't any backup cronjob set up.
(updated 2012-08-07 01:39:37)

You can try giving higher priority for warsow with nice.

Ok, changed the nice value to -19. I'll try it out later and see if it helps things.

No luck sadly. Still getting lag spikes even with only 5 people playing.

It's most likely disk usage from you, or someone else on the same machine.

Are you sure it's not the VPS host?

mebe its releated to the problem noon had where his log file was written only every xx minutes
...

clownfart wrote:
It's most likely disk usage from you, or someone else on the same machine.

jihnsius wrote:
Are you sure it's not the VPS host?

Both plausible. Although I'm fairly certain there is nothing else running on my VPS that would cause big disk usage spikes. I'm just eliminating other possibilities for now.

Mef!sto wrote:
mebe its releated to the problem noon had where his log file was written only every xx minutes
...

Can you elaborate a bit on this? How did writing to the log file cause lag? And was there a fix?

EDIT: Commented out set logconsole in dedicated.sh, to see if logging is somehow causing problems.
(updated 2012-08-13 22:12:26)

I don't think writing to a log file would cause lag at all, tbh. But it's worth checking if you can't find the cause.