Re: [SQU] How to tell if Squid is Overloaded?

On Wed, 29 Nov 2000, Dana Gourley wrote:

> I am using Linux-2.2.16
> I am using currently squid2.4Devel4 with async-io=160, two
> "cache_dir aufs /cache1/cache 4000 16 256"
> plus "cache_mem 32MB"
> I am using two IDE disks. One of them also does the logging.
> The polygraph test is a modified version of polymix-2. Similar things happen
> with polymix-2. The cache is full for these tests. The peak request rate
> was 74req/sec. Also occurs at 50req/sec

If my math is right, an 8GB cache can hold about 5 hours of fill
traffic at 74/sec request rate. This may be too small of a cache as
Polygraph working set is not managed using LRU while Squid cache is.

IIRC, Polygraph reports working set sizes on the console when WS is
being frozen. See if those values are at least 30% smaller than your
cache size. Also, keep in mind that PolyMix-3 has a better, more
realistic working set maintenance algorithms.

IIRC, Squid can report statistics that shows the number of objects not
cached due to overload. I do not recall the name of the variable
though...

Alex.

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