acngtool shrink is insufficient to maintain acng cache size
build-tails we call
acngtool shrink 10G before each build to prevent the cache from running out of disk space. From what I can tell it doesn't clean APT indices correctly, e.g. in my
/var/cache/apt-cacher-ng/time-based.snapshots.deb.tails.boum.org/debian I have snapshots dating back to January 2017. Each such snapshot takes 30-120 MB (especially the old ones with multiarch are large) so it adds up, for me to 8 GBs. :S
Either we need to improve
acngtool (for everyone's benefit) or we manually find snapshots older than six months (or whatever) and purge them from acng's cache.
intri suggested that acng's daily cronjob should be able to clean it up, but that it takes a long time: "(it fetches all dists again to identify obsolete packages) so I doubt we can do that at every build".
Or maybe not:
(17:25:53) intrigeri: ah ah on lizard, we do "rm -rf /var/cache/apt-cacher-ng/*.tails.boum.org" weekly, so no, the cronjob is not what saves us there.