Re: 20GB IDE and Redhat 6.0

From: Robert Dale <>
Date: Fri, 1 Oct 1999 18:14:47 -0400 (EDT)

On Fri, 1 Oct 1999, Clifton Royston wrote:

> > Don't forget to add memory. 20GB of cache requires something like 512MB
> > of memory.
> Is there anywhere this ratio is documented?
> In section 3.1 of the FAQ, it implies that 512MB is only required if
> you have around 45GB worth of cache, and in Martin Hamilton's sizing
> compilation <>, one user
> reports using 16GB of cache disk with only 128MB actual memory.

For every 128MB of used disk cache, you should have 1MB of real RAM.*

So, yes, you can have 16GB of cache disk with 128MB of RAM. But the
problem he may run into is when his disk cache approaches 100%. Don't
forget to add RAM for your system as well!

Also, unless you have cache on your disk controller, you'll want to
add additional RAM to cache your recent disk accesses otherwise all
your retrievals will be direct from disk.

Let's add it up. For a 20GB disk you'll want ~156MB of real RAM.
You'll probably want atleast 64MB for your system. And to cache
recent access, I would recommend atleast 128MB. Add it up and round
to the nearest logical number, you get 356MB. You'll only want to
go higher from here depending on how busy your server is.

*This is under the assumption Squid's data-types are stored somewhat
efficiently. I do not know Squid's internals. But, my calculations
seem to coincide with Real World experiences.

Robert Dale
		Live from!
Received on Fri Oct 01 1999 - 16:23:53 MDT

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