Re: [SQU] Ideal machine.

From: David Rees <dbr@dont-contact.us>
Date: Thu, 16 Nov 2000 00:30:20 -0800

Take a look at this document:
http://squid-docs.sourceforge.net/latest/html/c167.htm
It very well describes the hardware requirements of squid.

It's hard to say exactly how much hardware you'll need without knowing the
browsing habits of your users. Let's see if we can figure out how many
disks you'll need using the equasions given in the above URL. Assuming
you're maxing out 3 T1s worst case (4.5Mbps, your users can download about
2GB/hour. Assuming the average hit size is 13KB, that's about 150K hits
an hour, or 42 hits a second. Assuming a disk seek time of 12ms, each
disk will get you about 80 hits/second.

So theoretically (and if I did my math right ;-), a single disk should be
enough to handle the load you mention. Usually you want enough disk space
to cache at least a weeks worth of data, so assuming you move about 8GB
per day, you need 40GB of disk storage.

When you fill up this cache, you'll need almost 250MB of memory to store
the object index in memory. Then add in the squid memory cache and
filesystem cache sizes, and everything else and it fits quite nicely into
512MB RAM.

Given these requirements, I would say to shoot for 3 IDE disks (since
they're so cheap compared to memory):

Disk 1 on the primary IDE channel for the OS
Disk 2 on channel 1 of the secondary Promise IDE controller
Disk 3 on channel 2 of the secondary Promise IDE controller

Put half the squid cache on disk2, the other on disk3 and make sure you
use over 75-85% of the total disk space on those partitions as the speed
of the filesystem usually goes down drastically when it's nearly full.

-Dave

On Wed, Nov 15, 2000 at 11:44:21PM -0800, Squid Mailing List account wrote:
>
> We will be serviceing about 5000 clients. We will be feeding the servers
> (2 of them) a super cache feed from Satellite broadcast. The servers will
> also have access to our Internet Connections - 3 T1's. The goal is to
> reduce the load on our connections to the Internet.
>
> Thanks,
>
> Ken Rea
>
>
> On Wed, 15 Nov 2000, David Rees wrote:
>
> > On Wed, Nov 15, 2000 at 10:37:46PM -0800, Squid Mailing List account wrote:
> > >
> > > We're about to build a new squid server. What is the hot set up now days
> > > for a server keeping cost in mind. We're thinking about 512 Meg of ram and
> > > about 35 gigs of drive space. Is it best to use one big drive or to spread
> > > it out over several drives. If the latter what is the best way (keeping
> > > cost in mind) to achieve this?
> >
> > How much bandwith do you have, how many users will you be serving, and
> > what's your budget? What are your goals?
> >
> > For a budget minded squid server with good performance, try this:
> >
> > Duron 700
> > 512MB Ram
> > 2 15-20GB 7200rpm IDE drives, one on each channel.
> >
> > If you can spend another $125 each on a third or fourth drive, even
> > better, throw in an extra Promise PCI-ATA100 card or get the Asus A7V with
> > the Promise IDE card built in with a drive for each channel.
> >
> > Make sure each drive is on a separate cable and that you're using 80pin
> > cables.
> >
> > Then create 1 squid-cache directory on each drive, and away you go.
> >
> > If you run out of CPU power (unlikely for such an IO limited task), you
> > can always upgrade to the latest 1.2GHz Athlon with no other system
> > changes. Remember that squid is mainly IO (network and disk) limited, and
> > then memory limited. I doubt that CPU power will be much of an issue.
> >
> > -Dave
> >
> > --
> > To unsubscribe, see http://www.squid-cache.org/mailing-lists.html
> >
>

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Received on Thu Nov 16 2000 - 01:33:03 MST

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