On Monday 08 July 2002 04.54, Wei Keong wrote:
> Have some questions on siblings. Having more siblings will give
> higher siblings_hit and save bandwidth, but, will incur more
> processing and higher latency...
Yes. There is a tradeoff.
> Is there any optimum number of siblings that for a squid box? If
> cache digest is used, is there any way to estimate the latency?
The optimal depends on the distribution of the user populations using
each sibling, the user population using your Squid, cache sizes,
latency requirements etc..
You should periodically evaluate the effect of your sibling relations
to determine if the relation really brings any measurable benefit.
You do this by collecting statistics from access.log on how the
sibling has been used.. (see the hierarchy field), and put the
eventual savings this indicate in relation to the incurred latency
and local traffic overhead your sibling relation creates.. (each
CACHE_MISS generates a ICP query to the siblings).
Generally speaking, if you have more than 3 then you most likely have
several sibling relations that do not pay off..
Regards
Henrik
Received on Mon Jul 08 2002 - 04:21:24 MDT
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