# Increasing caching

# NOTE AT LEAST CACHE-MIN-TTL IF NOTHING ELSE!

# This has potential to increase memory usage to 110m under heavy usage, but
# I find that unlikely as almost everything is using so short TTLs
# See also MEMORY CONTROL EXAMPLE in man unbound.conf

server:
	# bytes in message cache, defaults to 4m
	msg-cache-size: 50m
	# bytes in rrset cache, defaults to 4m
	rrset-cache-size: 50m
	# nxdomain cache, default 1m
	neg-cache-size: 10m
	# Increases TTL of all queries to 900 seconds (5 minutes) if upstream has
	# a lower one. I have been using this since August 2019 without issues.
	# TODO FIXME
	#cache-min-ttl: 900
	# https://blog.apnic.net/2019/11/12/stop-using-ridiculously-low-dns-ttls/
	# dares setting the minimum cache to something between 40 minute and 60,
	# so how about 50 minutes? However it predates RFC 8767.
	# TODO FIXME
	cache-min-ttl: 3000
	# Why not just make it hour directly, while that is considered as a
	# maximum reasonableish value?
	cache-min-ttl: 3600
	# Update cache for popular items before they expire. ~10 % traffic
	# increase according to `man unbound.conf`
	prefetch: yes
	# Fetch keys when DS is encountered, lower latency for a bit higher CPU use
	prefetch-key: yes
	# Allow expired results to be served if they are in cache. The cache will
	# get updated the next time.
	serve-expired: yes
	# Serve expired data up to one day (RFC 8767)
	serve-expired-ttl: 86400
	# If serving expired data to client, explicitly give it TTL 30 seconds
	serve-expired-reply-ttl: 30
	# Serve expired data to client if there is no answer in 1.8 seconds as per
	# common timeout 2 seconds according to the RFC 8767
	#serve-expired-client-timeout: 1800
	# However my /etc/resolv.conf timeout is 1 second since all my nameservers
	# are localhost, so let's wait 0.8 seconds instead.
	serve-expired-client-timeout: 800
	# DNSSEC errors for expired records
	ede-serve-expired: yes

# vim: filetype=unbound.conf