[Pdns-users] Performance Tuning

[Michael Loftis]

This is what we're using at my place of emply.  We use six 
distributor-threads instead of three, and mysql 4.1 on debian woody with a 
2.4 kernel....machine's wors load average has been in the 1.0 range.  We're 
in a bit of a lull right now but it didn't seem to have too much of a 
problem keeping up.  The thing we had/have problems with is dnscached which 
is having issues keeping up with our load.  I ended up doubling it's 
compiled in outstanding-query-limit,  I still seem to get quite a bit 
slower response than BIND from the dnscached but atleast dnscached doesn't 
deadlock on us.

# cache-ttl     Seconds to store packets in the PacketCache
cache-ttl=20
# negquery-cache-ttl    Seconds to store packets in the PacketCache
negquery-cache-ttl=120
# query-cache-ttl       Seconds to store packets in the PacketCache
query-cache-ttl=20
# recursive-cache-ttl   Seconds to store packets in the PacketCache
recursive-cache-ttl=60

Uptime: 21.8 days Queries/second, 1, 5, 10 minute averages: 197, 193, 195. 
Max queries/second: 366
Cache hitrate, 1, 5, 10 minute averages: 56%, 58%, 59%
Backend query cache hitrate, 1, 5, 10 minute averages: 67%, 67%, 67%
Backend query load, 1, 5, 10 minute averages: 182, 175, 172. Max 
queries/second: 516
Total queries: 247899391. Question/answer latency: 1.76ms


--On December 14, 2005 12:28:47 PM -0800 Max Clark <max at clarksys.com> wrote:

> Hi all,
>
> I have a pdns instance running against a mysql backend. The machine is
> performing great and I will be consolidating additional servers/zones
> onto these boxes. Given a higher volume environment, what should I be
> using for the following configuration items:
>
># cache-ttl=20
># negquery-cache-ttl=60
># query-cache-ttl=20
># recursive-cache-ttl=10
>
> How do these values impact the system as a whole, what should I increase
> vs. keep the same?
>
> Thanks in advance,
> Max
>
> Uptime: 31 minutes Queries/second, 1, 5, 10 minute averages: 85.2, 89.5,
> 88.1. Max queries/second: 112
> Cache hitrate, 1, 5, 10 minute averages: 33%, 33%, 33%
> Backend query cache hitrate, 1, 5, 10 minute averages: 70%, 70%, 70%
> Backend query load, 1, 5, 10 minute averages: 117, 122, 120. Max
> queries/second: 146
> Total queries: 179972. Question/answer latency: 0.003ms
>
> --
>    Max Clark
>    max [at] clarksys.com
>    http://www.clarksys.com
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>



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