Re: replacement policy

On 27 Feb 1998, Stefan Monnier wrote:

> Yee Man Chan <ymc@eecs.umich.edu> writes:
> > I changed squid 1.1.20's to use Biggest File get replaced First
> > algorithm (are there any acronym for this one?). What I did was changed
> > the comparison function argument of qsort inside storeGetSwapSpace to a
> > function like this:
>
> That would be really neat since it would allow to increase the
> maximum_object_size without jeopardizing my cache.

Unfortunately, it may also decrease your _Byte_ Hit Ratio quite a bit. SIZE
algorithm (that is the official name for "biggest file first", if I remember
correctly) boosts Document Hit Ratio but decreases BHR. There are many better
algorithms that try to balance byte and document hit ratios (LRU-SIZE, for
example). However, all those are mostly "academic" attempts to publish a
paper :). In reality, all _good_ algorithms have very close HRs to
LRU-Threshold on large caches. (large with respect to your traffic volume,
not absolute size).

$0.02,

Alex.
Received on Fri Feb 27 1998 - 09:41:32 MST