On Fri, Sep 01, 2006, Mark Nottingham wrote: > I'd appreciate some enlightenment as to how Squid handles large files > WRT memory and disk. > > In particular; > - squid.conf says that memory is used for "in-transit objects." > What exactly is kept in memory for in-transit objects; just metadata, > or the whole thing?
Squid used to keep the whole thing in memory. It now: * can keep the whole object in memory * If memory is needed, and the object is being swapped out Squid will 'free' the start of the object in memory - the in-memory copy is then not used to serve replies but is just there to be written to disk. All subsequent hits come from disk. > - if something is in memory cache, does it get copied when it is > requested (because it is in-transit)? The whole object isn't copied during a memory hit; only the current '4k' range being read. > - How does sendfile support in 2.6 affect this? Sendfile support? :) > - Does anyone have any experiences they'd care to relate regarding > memory-caching very large objects? Not yet; but there's a project on my plate to evaluate this to begin caching p2p and youtube stuff a bit better.. Adrian
