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Diffstat (limited to 'middleware/cache/README.md')
| -rw-r--r-- | middleware/cache/README.md | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/middleware/cache/README.md b/middleware/cache/README.md index 68f13dbaf..dc1acba6d 100644 --- a/middleware/cache/README.md +++ b/middleware/cache/README.md @@ -4,20 +4,32 @@ ## Syntax -~~~ +~~~ txt cache [ttl] [zones...] ~~~ -* `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. +* `ttl` max TTL in seconds. If not specified, the maximum TTL will be used which is 1 hours for + positive responses and half an hour for negative ones. * `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 -value is used. +Each element in the cache is cached according to its TTL (with `ttl` as the max). +For the negative cache, the SOA's MinTTL value is used. A cache can contain up to 10,000 items by +default. + +Or if you want more control: + +~~~ txt +cache [ttl] [zones...] { + postive capacity [ttl] + negative capacity [ttl] +} +~~~ -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. +* `ttl` and `zones` as above. +* `positive`, override the settings for caching positive responses, capacity indicates the maximum + number of packets we cache before we start evicting (LRU). Ttl overrides the cache maximum TTL. +* `negative`, override the settings for caching negative responses, capacity indicates the maximum + number of packets we cache before we start evicting (LRU). Ttl overrides the cache maximum TTL. The minimum TTL allowed on resource records is 5 seconds. |