Re: Is proxy really efficient ???

From: Alex Rousskov <>
Date: Fri, 29 May 1998 09:54:16 -0600 (MDT)

On Fri, 29 May 1998, wrote:

> cache manager gives us a hit ratio of 0.35. So we think that 35% of the
> requests are directly answered by the proxy and gives a gain of approximately
> 35 % of our bandwith.

Usually, the savings in #transfers are 15-20% larger (absolute scale) than
the savings in transferred volume.

There are too kinds of hit ratios: document hit ratio (DHR) and byte hit
ratio (BHR). Which one is 35% in your case? Usually, DHR ~= BHR + 15% or so.
Small documents tend to be more popular which makes saving bandwidth harder
than saving #outgoing requests.

> But when looking at mrtg, the gain is only 5%
> between in/out traffic on the squid box's port.

If MRTG counts portion of total traffic saved, it should be closer to BHR.
There are a few "hits" that still consume some outbound bandwidth. For
example, TCP_REFRESH_HIT. I doubt, however, that the overhead can affect real
BHR significantly.

Received on Fri May 29 1998 - 08:58:06 MDT

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