On Tue, Feb 4, 2014 at 6:10 PM, John Plevyak <jplev...@gmail.com> wrote:
> You can pin stuff in the cache for a given time. There is also a bit > evacuation feature which should keep fresh content in the cache of it is > accessed with any frequency. > Is this second feature you are talking about the thing that evacuates content that is currently being served, or is there something else? > On Feb 4, 2014 10:21 AM, "Alan M. Carroll" <a...@network-geographics.com> > wrote: > >> For anyone who doesn't mind getting their brain dirty, there is some >> documentation on how the cache works here[1]. A key point to keep in mind >> is that the TS cache is a circular buffer, so "full" is a rather vague >> concept for it. That is, non-stale content can be evicted even if the cache >> is not technically full. >> >> [1] >> https://trafficserver.readthedocs.org/en/latest/arch/cache/cache.en.html >> >> Tuesday, February 4, 2014, 10:30:36 AM, you wrote: >> >> > A related question I have is what would be the best way to determine >> > if your cache misses are a consequence of otherwise fresh content >> > being evicted from the cache? >> >> That's quite difficult currently. My clients are not overly pleased with >> that situation either and I am currently working for them on improving the >> cache API to make this much easier. Hopefully I will be able to present >> some progress on this at ApacheCon/TS Summit. >> >> Because of the way the cache works, it's not really feasible for it to >> actually know if it is evicting non-stale content. One thing you could do >> is track cache write bytes and compare that to the total cache size, which >> should give you a rough estimate of how often the cache wraps. It might be >> reasonable to put in a specific statistic that counts such wraps. >> >> It would be possible to detect an eviction on a cache miss, somewhat >> reliably. I don't know if that is tracked specifically though. >> >>
