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Re: Hardware Upgrade: More RAM or SCSI?

On Fri, 2 Apr 1999, Jeff Hill wrote:

> Which is the better upgrade, more RAM or going to SCSI?
> Currently, I'm running a P150 with 96MB RAM on a fast IDE drive (7200
> RPM). I'm working on upgrading the server to slink with Apache-SSL.

Ok, so I assume you are running a 2.0 kernel. 

Be wary of upgrading past 128M because many motherboards can not cache
above this and you can actually SLOW performance by adding more RAM than
this (inactive tasks hogging low, cacheable RAM while an active task is
running in higher, uncached RAM).  I would try these things:

1. Run multiple CPU's even if they are an old Socket-7 mobo with P166's.
Even a P100 will keep up with a full T1 just fine.
2. Run a 2.2 kernel with the above. Better threading in the kernel.
3. Install a second ethernet interface, use round-robin DNS (two IP
addresses for the same hostname) to spread the load between the two
ethernet cards.
4. Convert any perl CGI scripts to compiled executeables or at least
convert to tcl or python.
5. Consider java servelets for some functions.
6. Look at such things as Velocigen

If you have multiple CPU's and multiple ethernet cards you can serve
multiple requests and with the granularity in the 2.2 kernels, you might
be able to handle network traffic with one CPU while handling disk traffic
with the other. You improve your chances of having one piece of hardware
available to handle an event while another is busy. Though you will not be
able to service one net card at the same time as you are servicing the
other (because of kernel locks) you might be able to overlap/interleve
some things.

You might also look at a threaded web server like JAWS. It gives you
a great performance boos over a process-diversity server like Apache when
running on an SMP system though I hear Apache is movong towards a threaded
design to take better advantage of multiple processors.


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