named cleaning interval

Mark.Andrews at nominum.com Mark.Andrews at nominum.com
Fri Nov 24 21:57:32 UTC 2000


> 
> Well, I will make some testings with different interval values and monitor
> the queries and answers parameters.
> I just wanted to know if somebody already experienced that.
> 
> I can add that the cleaning concerns about 4000 to 13500 RRs each time. 
> I have a master server and a slave one. Both show these results.
> 
> thank you

	If cache cleaning is noticable you most probably don't
	have enough real memory and the server is paging heavily
	while the cache is being cleaned and for a short time
	afterwards as it gets back to a useful working set of
	pages.

	Mark
> 
> 
> 
> -----Original Message-----
> From: Jim Reid [mailto:jim at rfc1035.com]
> Sent: Friday, November 24, 2000 2:08 PM
> To: Julien Mabillard
> Cc: bind-users at isc.org
> Subject: Re: named cleaning interval 
> 
> 
> >>>>> "Julien" == Julien Mabillard <jum at cw.span.ch> writes:
> 
>     Julien> So my question is, for several thousands of hosted zones,
>     Julien> what should be the cleaning interval for tuning the
>     Julien> performance of the bind server?
> 
> It depends. The default cleaning interval should be "good enough" for
> most name servers. Whether its good enough for you depends on things
> you've not told us (and probably don't know yourself). For instance,
> how long (on average) it takes to clean the cache; how much of the
> name server's data structure is cached RRs and how much is used by the
> RRs loaded off zone files; what percentage of the traffic is queries
> for names the server can answer authoritatively and what percentage
> involves your name server querying other servers; how many system
> queries does your server make; what fraction of queries come from
> other name servers and what come from stub resolvers; etc, etc.
> 
> If lots of people are noticing that the server isn't responding
> because cache cleaning takes too long, you probably should use a
> longer cleaning interval. Hopefully this would mean the cleaning
> (garbage collection actually) took place at times when your users
> weren't querying the server. OTOH, if the cleaning interval was
> shorter, it's possible that the time taken to do the clean up would be
> lower because each run had fewer expired RRs to get rid of and
> therefore had less work to do.
> 
> Personally, I doubt if anyone will notice the cache cleaning outages.
> And if they did, there are better ways to solve the problem. One would
> be to separate the name servers used to serve the zones to other name
> servers from those used by stub resolvers to make queries. Another
> would be to run a threaded name server such as BIND9 which can walk
> and chew gum at the same time.
> 
> Why don't you experiment with different cleaning intervals and report
> your findings here?
> 
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com



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