Re: Measuring DNS Performance & Graphing Logs

[Jared Mauch <jared () puck nether net>]

> On May 21, 2015, at 12:00 PM, charles () thefnf org wrote:
>
> > can u suggest some suitable tools that i can measure the performance of the
> > dns servers?
>
> What sort of performance? What metrics are you trying to track? Please provide more details about exactly what you 
> want.
> That will help us give you very specific suggestions. (We provide advice for free, have very busy schedules, the more 
> specific
> you are the better).

At the recent DNS-OARC meeting there was an interesting discussion about a new tool called DNSDIST.  It’s part of 
PowerDNS and there is also a independent tar one can fetch.

What is interesting about it is it can report on a lot of data about the performance of your DNS servers.   Some people 
use a load balancer, and this will do that but be application aware and can easily route certain types of queries to 
another server.  (e.g.: arpa requests to dedicated servers, same as domains that may be used/abused).

It provides realtime graphs of CPU usage and query rates as well as average response times.

You can set query rate limits and it will balance as you specify.  This is useful as many people who know/use Linux 
have seen the issues with UDP kernel performance.  If you’re not aware, do this: 

UDP:

iperf -s -u
iperf -u -c localhost -b 25000m

eg:
[  3]  0.0-10.0 sec  4.50 GBytes  3.87 Gbits/sec   0.000 ms 84054/3374408 (2.5%)

vs

TCP:

iperf -s
iperf -c localhost
[  3]  0.0-10.0 sec  56.1 GBytes  48.2 Gbits/sec

- Jared