[Pdns-users] 8% cache hits

[BH]

You could try extending the cache size and TTL, but I am not sure how
effective that will be in this situation.

First thing is as its an RBL, do you really want to cache entries for a
long time? After an entry has been removed from a blacklist (eg. in the
case of a legit mail server sending out spam, then getting removed) it
will take a longer period of time before that server is able to send you
mail again.

With mail servers you do get a large amount of connections from people
trying to blast spam, that means you will have a large amount of queries
for random IP's being done which isn't very effective for a cache - its
there to help with look ups of the same thing.

You should be able to generate some stats from your mail logs to check
how many connections you have from different IP's and work out a
reasonable estimate of the cache effectiveness.


On 16/10/2011 12:33 AM, Aleksandar Lazic wrote:
> Dear readers,
> 
> I use
> 
> PowerDNS recursor 3.3 (C) 2001-2010 PowerDNS.COM BV (Sep 21 2010,
> 18:22:46, gcc 4.4.1)
> 
> with default settings (this means I have no settings changed!) on
> 
> Ubuntu 10.04.3 LTS
> 
> The PowerDNS recursor is primary used for DNS RLBs
> 
> b.barracudacentral.org
> zen.spamhaus.org
> ix.dnsbl.manitu.net
> 
> My main question is how I can increase the cache hit %?
> 
> ###
> pdns_recursor[17799]: stats: 317639 questions,
>                               81071 cache entries,
>                                8601 negative entries,
>                                  8% cache hits
> 
> pdns_recursor[17799]: stats: throttle map: 2, ns speeds: 631
> pdns_recursor[17799]: stats: outpacket/query ratio 96%, 0% throttled, 0
> no-delegation drops
> pdns_recursor[17799]: stats: 3 outgoing tcp connections, 1 queries
> running, 5546 outgoing timeouts
> pdns_recursor[17799]: stats: 57911 packet cache entries, 31% packet
> cache hits
> pdns_recursor[17799]: stats: 0 qps (average over 1967 seconds)
> ###
> 
> Please can anybody point me to the right direction of link ;-O
> 
> Thanks Aleks
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