Blinkenlights.nl
Software
DJBDNS dnscache tuning
A Patch for dnscache, which solves issues encoutered when running heavily loaded servers.
Poll/MAX_UDP
Dnscache has some problems with high load, by default it is limited to 200 concurrent queries ( MAX_UDP in dnscache.c ), raising this limit increases the poll frequency as well ( this really needs a smarter algorithm ). Another issue is that dnscache only handles 1 packet each poll, making dnscache handle all available packets each poll increases performance considerably. I found a patch which solves this issue somewhere on the internet, the site which hosted it seems to have vanished.
So Long and thanks for all the Fish