This document is about PowerDNS 4.0. For other versions, please see the documentation index.

RecursorĀ Statistics

The rec_control get command can be used to query the following statistics, either single keys or multiple statistics at once:

In the pdns/tools/rrd/ subdirectory a number of rrdtool scripts is provided to make nice graphs of all these numbers. Use rec_control get-all to get all statistics in one go.

It should be noted that answers0-1 + answers1-10 + answers10-100 + answers100-1000 + answers-slow + packetcache-hits + over-capacity-drops + policy-drops = questions.

Also note that unauthorized-tcp and unauthorized-udp packets do not end up in the 'questions' count.

Every half hour or so, the recursor outputs a line with statistics. More infrastructure is planned so as to allow for Cricket or MRTG graphs. To force the output of statistics, send the process a SIGUSR1. A line of statistics looks like this:

Feb 10 14:16:03 stats: 125784 questions, 13971 cache entries, 309 negative entries, 84% cache hits, outpacket/query ratio 37%, 12% throttled

This means that there are 13791 different names cached, which each may have multiple records attached to them. There are 309 items in the negative cache, items of which it is known that don't exist and won't do so for the near future. 84% of incoming questions could be answered without any additional queries going out to the net.

The outpacket/query ratio means that on average, 0.37 packets were needed to answer a question. Initially this ratio may be well over 100% as additional queries may be needed to actually recurse the DNS and figure out the addresses of nameservers.

Finally, 12% of queries were not performed because identical queries had gone out previously, saving load on servers worldwide.