Memory usage BIND 9.2.1

phn at icke-reklam.ipsec.nu phn at icke-reklam.ipsec.nu
Wed Jul 10 09:31:48 UTC 2002


Dave Ellenberger <removethis-dave at nofuture.ch> wrote:
> Hi

> First sorry for not reading the whole BIND manual ;-)
> I have like ~2000 domains on a primary DNS server and was using BIND
> 8.<latestversion> some time ago. When checking the process list with ps the
> process named was using about 90 MB RAM when starting up the service and
> after a few days it was at ~120MB or such.

> With BIND 9.2.1 it takes like 80 MB RAM when starting up service and it
> raises up to 220MB+ during a week. The server "only" has 256MB RAM. "free"
> displayes that there's like 30 MB data on swamp partition. Most information
> on DNS cache should have TTL of 1 day, that's why I don't see why memory
> usage still is rising after a week...

> Is there a way to tell BIND 9.2.1 to free up memory or only use a fixed
> amount of memory? Of course caching DNS queries is very important, but
> somewhen it might slow down if the required data is on swap partition. Thats
> why it might be better to clear some cache data and (let's say) 50% more
> DNS queries instead of caching the data the whole duration defined in TTL
> instead of putting data in swap partition. Retrieving the DNS quiery from a
> non-local server might be still faster than reading from swap...

> If I upgrade to 512MB RAM, do you think that BIND 9.2.1 will stop at e.g.
> 250MB RAM usage? Or after a month it will be at 1GB RAM?

> Why does BIND 9.2.1 use so much more RAM than 8.<latestversion>?

A nameserver caches information retreived by it's clients. The data
itself is under control of other organizations, that will use whatever
TTL they like. bind-9 uses another memory model, that might cause 
memory consumption to be different from your previous brand.

The amount of memory neededd for a "resolving nameserver" is a function
of client activity, TTL of the data and size of the data. The only
part you can control is your clients ( but do you want to ?).

The answer to your concerns is "buy more memory". And no, memory
usage will not grow indefinitly, it will flat out after a week or so 
(unless your clients changes habits).

If your memory chips is very expensive ( using brand-name computers ??) you
might find a reason to purchase some other hardware. Welcome back
for a discussion of viable alternatives.

> Dave




-- 
Peter Håkanson         
        IPSec  Sverige      ( At Gothenburg Riverside )
           Sorry about my e-mail address, but i'm trying to keep spam out,
	   remove "icke-reklam" if you feel for mailing me. Thanx.


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