title: PowerDNS Authoritative Server: Caches
agents: linux
catalog: app/powerdns
license: GPLv2
author: Christian Wirtz
distribution: powerdns-mkp
description:
 Monitors the packet cache and the query cache of the authoritative server.

 The hit ratios are computed from the change of the hit and miss counters since
 the previous check rather than from their absolute values. That way the ratio
 describes current behaviour instead of the average since the last restart,
 which is what you want when you are looking for a cache that stopped working.

 Cache sizes are reported for the packet cache, query cache, key cache,
 metadata cache and signature cache. The deferred insert and lookup counters
 indicate contention on the cache locks and have upper levels by default.

 No levels are set on the hit ratios out of the box, because a sensible lower
 bound depends entirely on your query mix.

discovery:
 One service is created when packet cache or query cache counters are present.
