Unbound cache is lost upon container restart

[preethamvishy]

When the pihole-unbound container is recreated/restarted, unbound appears to be building cache from scratch and there's a high number of cache misses compared to cache hits. Since you really reap the benefits of unbound's cached DNS resolution once the cache builds up, a restart of the container for any reason appears to undo the cache built up.

Is there a way to persist the unbound cache across restarts?

total.num.queries=584
total.num.queries_ip_ratelimited=0
total.num.cachehits=57
total.num.cachemiss=527
total.num.prefetch=2
total.num.expired=0
total.num.recursivereplies=527
total.requestlist.avg=3.0794
total.requestlist.max=44
total.requestlist.overwritten=0
total.requestlist.exceeded=0
total.requestlist.current.all=0
total.requestlist.current.user=0
...
time.up=883.899163
time.elapsed=883.899163

[burnbabyburn]

By default unbound stores cache in memory and thus it's normal to loose cache on restart. You need cachedb as described in the unbound documentation and ofc need a seperate docker volume to store unbound cachedb or an additional redis container. If you want to change default behaviour, you would have to invest some time (especially for the 2 container version in this repo)

But LMGTFY
Check if unbound has been compiled with --enable-cachedb
Setup cachedb config with or without redis backend - official documentation