named gets swapped in and out

Kevin Darcy kcd at
Sat Jan 11 00:21:38 UTC 2003

Ignacio wrote:

> Hello.
> Our primary DNS (bind v 9) gets swapped in and out after a time.  When
> I restart it, named begins well with 20MB of memory (the  amount of
> resident memory of the process), until it reaches 90MB and it gets
> swapped.  Then some clients can't make queries.
> What could be the problem?  It could be hardware or some wrong bind
> configuration?  Shuld I change max recursive-clients, max-cache-size
> or something like this?
> Our system is:
> --------------
> Pentium II - 333 MHz
> 93MB Ram
> FreeBSD 4.5

It would seem that you have too little RAM for the variety/mix of queries
that you're servicing and/or the respective cache persistence of the
responses to those queries (i.e. their TTL values). The simple answer is
"buy more RAM". Failing that, you _could_ tweak max-cache-size, but that
just conserves RAM resources at the expense of CPU and network resources,
and will probably hurt query latency as well. You could also try tuning
max-cache-ttl and/or max-ncache-ttl, since it's possible that a
relatively small number of infrequently-queried cached positive or
negative responses are consuming a disproportionate amount of cache
resources, at the expense of everything else.

- Kevin

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