Limiting memory usage

[phn at icke-reklam.ipsec.nu]

Udo Erdelhoff <ue at nathan.ruhr.de> wrote:

> Hi,
> I am having some trouble with limiting the memory usage of BIND.
> The box in question is a Sun Netra T4 (2x750 MHz) that runs BIND
> 9.2.0 on top of Solaris 8 and is a moderatly busy resolver (about
> 500-700 queries/sec, depending on the time of day).  The box only
> has 512 MByte of RAM (another 512M are on their way, but that's
> beside the point) and I had to configure 10.000 clients.

I don't think you can (in a reasonable way) limit a nameservers
memory hunger. It's a function of the clients usage and TTL values
set in the RR.  Trying to enforce lower TTL will break the
original RR-publishers suggestion.

Unless you have a faulty app that is eating memory, ( you have 
disabled CDE ??) there is no cure but more memory.


> Every once in a while, the box runs out of memory and starts paging.
> BIND performance drops to about 9 queries/sec and the only way to fix
> this is to restart BIND.

> I already set the maximum cache size to 100 MByte.  According to the
> data in the ARM, the 10.000 clients add another 200 MByte.  When the
> box starts paging, named is using about 420 MByte.  Using datasize
> to put a hard upper limit on the memory usage is A Bad Idea(tm),
> rndc dies due to lack of memory and things go downhill after that.

> And now for the $64.000 question: What is using the extra memory?
> And is there a way to limit it?

> The extra memory will help in the sense that BIND will survive
> longer before I need to restart it.  And if I manage to get to a
> point where the thing runs for 24 hours without a need to restart,
> I can do a 'scheduled restart for maintainance' each night to flush
> the cache.  But it would be really great if the thing ran without
> the need for daily restarts.  This IS a unixiod box, after all, not
> some Windows claptrap :-)

> /s/Udo
> -- 
> After the night I've had, on top of the year that I've had, what I really
> want is a nice vile kill. But since that's currently off the menu, I'll
> have to settle for a few stiff drinks.


-- 
Peter Håkanson         
        IPSec  Sverige      (At the Riverside of Gothenburg, home of Volvo)
           Sorry about my e-mail address, but i'm trying to keep spam out.
	   Remove "icke-reklam" and it works.