> Of the objects that are being nuked/evicted, were they close to their > natural expiration time anyway? Were they ever used to serve a cache > hit? > > Of the objects that have been nuked, are they requested shortly after, > suggesting it may have been worth having a larger cache in order to > retain them a bit longer? > > I did not see an easy way to answer these questions with the standard > Varnish toolset - am I missing something?
I think you are correct. The grace period could also be responsible for keeping expired objects around and making them good candidates for LRU eviction. > I looked through the code paths in Varnish 5.1 responsible for > expiration and nuking and it seems the object hit count and ttl is > available in that context - would it be worth writing a patch to log > these fields to the VSL? You could add a `t=%f` to the `ExpKill LRU` log records, and introduce something like a `h=%d` for hits and add it to the LRU and EXP_* variants of the ExpKill record. See `man vsl` for Expkill. I'm not sure such a patch would be accepted as we usually are cautious with the VSL throughput but at least I would gladly review it (merging's not my call in this area). Dridi _______________________________________________ varnish-misc mailing list [email protected] https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
