download the new version Quick CPU 4.6.0

This prevents a single thread from having to handle every incoming queries, but can lead to thundering herd issues where all threads are awoken at once when a query arrives. If pdns-distributes-queries is set to no and either SO_REUSEPORT support is not available or the reuseport directive is set to no, all worker threads share the same listening sockets. If the incoming query rate is so high that the dispatch thread becomes a bottleneck, you can increase distributor-threads to use more than one. The dispatch thread enabled by pdns-distributes-queries tries to send the same queries to the same thread to maximize the cache-hit ratio. The latter is the default since version 4.9.0. When running with several threads, you can either ask PowerDNS to start one or more special threads to dispatch the incoming queries to the workers by setting pdns-distributes-queries to yes, or let the worker threads handle the incoming queries themselves.

Set threads to your number of CPU cores minus the number of distributor threads. Please check and if necessary raise sysctl _size. When deploying (large scale) IPv6, please be aware some Linux distributions leave IPv6 routing cache tables at very small default values. See below for more information about the various caches.

Limit the size of the caches to a sensible value.Ĭache hit rate does not improve meaningfully beyond a few million max-cache-entries, reducing the memory footprint reduces CPU cache misses. This can be raised using the ulimit command or via the LimitNOFILE unit directive when systemd is used.įreeBSD has a default limit that is high enough for even very heavy duty use. Linux by default restricts processes to 1024 file descriptors, which should suffice most of the time, but Solaris has a default limit of 256. To get the best out of the PowerDNS recursor, which is important if you are doing thousands of queries per second, please consider the following.Ī busy server may need hundreds of file descriptors on startup, and deals with spikes better if it has that many available later on.

Conversion of old-style settings to YAML format.

Cryptographic software and export control.

Tuning Incoming TCP and Out-of-Order processing.

PowerDNS Recursor New Style (YAML) Settings.

Download the new version Quick CPU 4.6.0