Mirrors/coredns
1
0
Fork 0
mirror of https://github.com/coredns/coredns.git synced 2025-10-27 08:14:18 -04:00
Code Issues Packages Projects Releases Wiki Activity

plugin/cache: Document actual cache defaults (#2249)

Browse Source
This commit is contained in:
Chris O'Haver
2018-10-29 11:03:59 -04:00
committed by GitHub
parent dc85f14e5c
commit 29f4205364
1 changed files with 4 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
plugin/cache/README.md vendored
View File

@@ -24,8 +24,8 @@ cache [TTL] [ZONES...]
* **ZONES** zones it 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 (with **TTL** as the max). Each element in the cache is cached according to its TTL (with **TTL** as the max).
A cache is divided into 256 shards, each holding up to 512 items by default - for a total size A cache is divided into 256 shards, each holding up to 39 items by default - for a total size
of 256 * 512 = 131,072 items. of 256 * 39 = 9984 items.
If you want more control: If you want more control:
@@ -53,7 +53,8 @@ cache [TTL] [ZONES...] {
## Capacity and Eviction ## Capacity and Eviction
If **CAPACITY** is not specified, the default cache size is 10,000 per cache. The minimum allowed cache size is 1024. If **CAPACITY** _is not_ specified, the default cache size is 9984 per cache. The minimum allowed cache size is 1024.
If **CAPACITY** _is_ specified, the actual cache size used will be rounded down to the nearest number divisible by 256 (so all shards are equal in size).
Eviction is done per shard. In effect, when a shard reaches capacity, items are evicted from that shard. Eviction is done per shard. In effect, when a shard reaches capacity, items are evicted from that shard.
Since shards don't fill up perfectly evenly, evictions will occur before the entire cache reaches full capacity. Since shards don't fill up perfectly evenly, evictions will occur before the entire cache reaches full capacity.