.. SPDX-License-Identifier: GPL-3.0-or-later .. _performance: ************************** Performance and resiliency ************************** For DNS resolvers, the most important parameter from performance perspective is cache hit rate, i.e. percentage of queries answered from resolver's cache. Generally the higher cache hit rate the better. Performance tunning should start with cache :ref:`cache_sizing` and :ref:`cache_persistence`. It is also recommended to run :ref:`systemd-multiple-instances` (even on a single machine!) because it allows to utilize multiple CPU threads and increases overall resiliency. Other features described in this section can be used for fine-tunning performance and resiliency of the resolver but generally have much smaller impact than cache settings and number of instances. .. toctree:: :maxdepth: 1 daemon-bindings-cache systemd-multiinst modules-predict modules-prefill modules-serve_stale modules-rfc7706 modules-priming modules-edns_keepalive daemon-bindings-net_xdpsrv