diff --git a/middleware/cache/README.md b/middleware/cache/README.md index 187fc0ff3..68f13dbaf 100644 --- a/middleware/cache/README.md +++ b/middleware/cache/README.md @@ -8,24 +8,24 @@ cache [ttl] [zones...] ~~~ -* `ttl` max TTL in seconds, if not specified the TTL of the reply (SOA minimum or minimum TTL in the +* `ttl` max TTL in seconds. If not specified, the TTL of the reply (SOA minimum or minimum TTL in the answer section) will be used. -* `zones` zones it should should cache for. If empty the zones from the configuration block are used. +* `zones` zones it should cache for. If empty, the zones from the configuration block are used. -Each element in the cache is cached according to its TTL, for the negative cache the SOA's MinTTL +Each element in the cache is cached according to its TTL. For the negative cache, the SOA's MinTTL value is used. -A cache mostly makes sense with a middleware that is potentially slow, i.e. a proxy that retrieves -answer, or to minimize backend queries for middleware like etcd. Using a cache with the file +A cache mostly makes sense with a middleware that is potentially slow (e.g., a proxy that retrieves an +answer), or to minimize backend queries for middleware like etcd. Using a cache with the file middleware essentially doubles the memory load with no conceivable increase of query speed. The minimum TTL allowed on resource records is 5 seconds. -If monitoring is enabled (`prometheus` directive) then the following extra metrics are added: +If monitoring is enabled (via the `prometheus` directive) then the following extra metrics are added: * coredns_cache_hit_count_total, and * coredns_cache_miss_count_total -They both work on a per zone basis and just count the hit and miss counts for each query. +They both work on a per-zone basis and just count the hit and miss counts for each query. ## Examples