Jeff Anderson wrote: > I'd like to see individual object request statistics and a method to > prefetch objects from the backend that are most frequently requested. > Perhaps also a way to prioritize objects into cache tiers based on > frequency of requests. So, for example, highly requested objects are > maintained in RAM and less frequently requested objects are cached to > disk.
Your operating system already does this today with Varnish. Squid tries to maintain a two tier cache hierarchy without success. > If persistent storage is on its way maybe a method to assign > priority to large disk cache volumes versus memory regions. Noted. > It might be nice to have a distributed and/or tiered cache model where a > single > master has a very large cache and potentially very long grace ability > where objects can exist even if stale. That master in turn could host > frontend caches that communicate efficiently to the master cache and > also have a tiered internal object priority. I believe most of this can be achieved today. Stale objects will hopefully reach the 2.0 series before the 2.1 revolutions - at least as a patch, I hope. > > Thanks, > --Jeff > > > On Jan 8, 2009, at 2:29 AM, Tollef Fog Heen wrote: > >> Hi, >> >> a short while before Christmas, I wrote up a small document pointing >> to >> what I would like to get into 2.1 and when I'd like milestones to >> happen. This is a suggestion, I'm open to ideas and comments on both >> feature set as well as if my guesstimates for dates is completely off: >> >> Varnish 2.1 release plan >> >> The theme for Varnish 2.1 is "scalability", particularly trying to >> address the needs of sites like finn.no which has a lot of objects and >> where priming the cache takes a long time, leading to long periods of >> higher load on the backend servers. >> >> The main feature is persistent storage, see >> http://varnish.projects.linpro.no/wiki/ArchitecturePersistentStorage >> for design notes. Another important scalability feature is a new >> lockless hash algorithm which scales much better than the current >> one. Poul-Henning already has an implementation of this in the tree, >> but it's still fresh. >> >> Minor features which would be nice to get in are: >> >> * Web UI, showing pretty graphs as well as allowing easy configuration >> of a cluster of Varnish machines. >> >> * Expiry randomisation. This reduces the "lemmings" effect where you >> end up with a many objects with almost the same TTL (typically on >> startup) which then expire at the same time. The feature will allow >> you to set the TTL to plus/minus X %. >> >> * Dynamic, user-defined counters that can be read and written from VCL >> >> * Forced purges, where a thread walks the list of purged objects and >> removes them. >> >> The schedule >> ------------ >> >> Alphas: >> - 2009-01-15: New hash algorithm working >> - 2009-02-15: Web UI >> - 2009-03-15: Persistent storage >> Beta: >> - 2009-04-01: Feature complete >> Release >> - 2009-05-20: Release candidate >> - 2009-05-01: No release critical bugs left >> - 2009-05-10: Release >> >> -- >> Tollef Fog Heen >> Redpill Linpro -- Changing the game! >> t: +47 21 54 41 73 >> _______________________________________________ >> varnish-misc mailing list >> [email protected] >> http://projects.linpro.no/mailman/listinfo/varnish-misc > > --Jeff > [email protected] > > > > _______________________________________________ > varnish-misc mailing list > [email protected] > http://projects.linpro.no/mailman/listinfo/varnish-misc -- Per Buer - Leder Infrastruktur og Drift - Redpill Linpro Telefon: 21 54 41 21 - Mobil: 958 39 117 http://linpro.no/ | http://redpill.se/
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