[Pdns-users] 8% cache hits

[Aleksandar Lazic]

Hi,

On 16.10.2011 06:02, BH wrote:
> 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.

Ok looks like you are right.

###
       9 59.182.175.18
       9 116.127.112.113
       7 175.100.99.4
       5 120.165.23.230
       5 125.33.58.188
       5 41.191.250.26
       5 178.126.81.188
       4 117.193.194.101
       4 112.135.50.5
       3 182.178.193.97
       3 182.185.22.115
       3 41.188.52.74
       3 124.6.181.213
       3 115.249.64.249
       3 120.68.190.240
       3 94.44.190.16
###

and these are the most often.

I have 697 only once connected.

So it looks like I must life with the 8% cache hits.

Thanks for your time and infos.

BR
Aleks

> 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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>
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