Hello Jason, Just an idea, before patching: log obj.hits and obj.age to get an idea of what you are delivering.
-- Guillaume Quintard On Nov 7, 2017 07:23, "Jason Stangroome" <[email protected]> wrote: > Hello, > > For at least one site that I am using Varnish Cache for, the allocated > cache size is fully utilised and objects are now being nuked/evicted > from the cache. Before I blindly supply more resources to provide a > larger cache, I'd like to understand if the cache space is being used > optimally. > > For example, of the objects that are expiring naturally, were they > ever used to serve a cache hit? If not, it was probably wasteful to > store them in the cache in the first place. > > 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 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? > > How do others ensure their allocated cache size is well utilised > before growing the cache? > > Regards, > > Jason > _______________________________________________ > varnish-misc mailing list > [email protected] > https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc >
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