Recursion ceases for 5-10 minutes at random intervals throughout, the day

[Bill Springall]

I apologize, Daniel, I lost your message at work...

We did run into the same problems, from what I have heard from the 
previous DNS admin.   He was actually a little nervous about me opening 
the cache on the servers with this new release under customer load.  To 
appease him after the problem cropped up I added the old values back 
into our include for named.conf (with his comments) for some soak time:

         max-cache-size 400m;    //max cache size 400MB
         cleaning-interval 30;   //clean cache every 30 minutes
and
         max-cache-ttl 60;       //limit cached records to a 60s TTL
         max-ncache-ttl 60;      //limit cache neg. resp. to a 60s TTL

I'm glad the developers fixed the issues.   I have wondered how much 
work those last servers actually had to do to keep up.

Unfortunately, I can't lock down the ip blocks any further, although I 
have certainly wanted to after a select few abusive customers have tried 
to go on all night nxdomain/servfail-fests.

Thanks for your response!

- Bill

 > We had similar problems with earlier BIND versions, once the cache size
 > hit certain level, server started to drop queries at short, irregular
 > intervals. We have found out that there was a relation to regular cache
 > maintenance bind does. The problem disappeared in later versions when 
BIND
 > started to use more efficient memory allocator, but you might have 
heavier
 > querry traffic.
 >
 > If you provide DNS resolver to a limited base of users, try to limit
 > recursive queries to IP blocks of your clients - spammers using open DNS
 > resolvers for massive MX record searches eat a lot of memory, since each
 > recursive query allocates some.
 >
 > Hope it helps somehow, write me for details if you wish.
 >
 > Best Regards
 >
 > Daniel Ryslink
 > System Administrator
 >