[K12OSN] Need Help

pogson robert.pogson at gmail.com
Sun Jul 8 00:39:53 UTC 2007

This is a realistic scenario. We are faced with a problem on an unknown
battlefield. How to survive?

1) Re-think the need to keep some/any of that other OS ('98, 2000, ME).
If the need to keep is due to fear and uncertainty, it might be better
to keep one or two working as usual and incorporate them later if, as I
did, you find Linux meets all needs. Are these machines properly
licensed? Do you have installation CDs for them? If you have any doubts
about these last two questions, you should not hesitate to wipe the hard
drives. You do not need the aggravation of tens of thousands of bugs,
licence issues, lack of suport, and so on. 

2)Try to visit each machine with a live CD like KNOPPIX
( http://knopper.net/knoppix/index-en.html ). 
ethtool eth0
will tell you much. You may find it useful to record the data. The
MAC/hardware address may be useful for configuring DHCP.

3)Study your RAM/CPU speed. You may have enough MIPS on a few machines
to run an LTSP server as a cluster of a few machines. Instead of
buying/building a new server, you could save hardware dollars and
increase reliability by have two or three lesser servers. Management
will be a bit more complicated, but learning is fun, right? You likely
want 100 MHz per client and 50 MB per client plus about 512MB extra
memory on each "server". If you find some candidates for servers, run
memtest86 on them and check memory bandwidth. Some Celerons and the like
have pretty good specs but memory bandwidth is incredibly low. A good
server is something like AMD64 X2 3800 with 1MB cache so look for
machines with 1000MHz or better and at least 256MB caches. DDR400 memory
would be fast enough for your setup, 3 gB/s memory bandwidth. If you can
get a few machines that total up to something like that, upgrade them by
adding RAM and perhaps a gigabit/s NIC. That will be cheaper than buying
a good server. You can use the saving to buy a network switch with some
gigabit ports. Otherwise, a suitable server would likely cost over
$1000. Using a cluster IN the lab is a bit risky. You may need to cover
the power/reset switches and place reminder signs to leave them on. If
you can delay buying the server, you will end with a better system
because performance/$ keeps improving.

4)If you must obtain a new server, please, check out the manual
including all specs and motherboard flowchart to be certain of hardware
compatibility and absence of bottlenecks. For example, a 32bit system
may look like it has the specs you need but you may find a gigabit/s NIC
on a PCI bus uses all the bandwidth and there is no more for hard
drives. Many AMD64 motherboards I have studied appear to be able to run
CPU/memory/a bunch of drives/a couple of gbit/s NIC at nearly full speed
all day long, which really helps a  LTSP server be snappy. Fortunately,
competition between Intel and AMD is intense so great prices abound.
Dual core/dual processor is a huge advantage with LTSP because there are
plenty of processes to go around to each core/processor. Last year, I
bought AMD64 X2 3800 for $200 CDN. This year, it is less than $100 CDN.
Good timing! You can also buy much faster processors. I have always
built my new servers so I can be sure what is in there.

5)Please use gigabit/s cat 6 networking for all servers. One gigabit/s
line can easily handle your lab. 100 mb/s can too, but you, and your
users will know when things get busy. Gigabit to 100 mbit switches are
pretty cheap these days.

6)Please use RAID 1 on your server. This is slower for writes
(installation and saving files) but allows simultaneous seeks for
simultaneous users/pocesses. Hard drives are about 25 cents a gB for 500

7)Around 1999 many PCs began to have NICs on the motherboard. On some of
these, you can press F8 to bring up a boot menu giving an option of
PXE/network booting from your server or booting from the hard drive. You
would not even need to install a boot loader to use that, if you posted
signs by each computer. Unfortunately, if you have '98, you are in that
time range where things changed. You can install a boot loader on the
MBR, but it would be easy to mess up your booting of that other OS. Do
not forget booting from the CD. You could have CDs hanging on the wall
which would boot from your server. CDs are much more reliable than
floppies. Whatever the boot medium, you need a driver for every NIC in
your place. If you happen to not have a driver, you will need to install
an additonal NIC.

8)If you can blow away that other OS, you have more options: installing
a bootloader on the hard drive, installing a minimal system (+
x-window-system and gdm) and connecting via X to the server, or
installing a complete Linux distro with the option to connect via X to
the server from the GNOME menu, and dual-booting (please, don't inflict
that other OS on your students).

Good luck. I would be glad to help, but I am 500 miles away.

Robert Pogson

On Sat, 2007-07-07 at 12:00 -0400, k12osn-request at redhat.com wrote:

> "Don Gould" <don at myfam.com>
> Subject: [K12OSN] Need Help
> To: k12osn at redhat.com
> Message-ID: <380-2200776712480644 at myfam.com>
> Content-Type: text/plain; charset=iso-8859-1
> To anyone listening,
> I am the Technology guy at a small christian school and I have been
> to to seminars.  I am ready to make the leap to K12osn.
> What I have :
> 30 computers in the lab
> 24 stand alone
> 6 networked internet machines
> all are windows 98, 2000 or ME
> 9 printers 4 of which work
> I need to get a server or build one.  But I need to know what I need
> in the server.  I nned to keep the win os for stand alone use.  But I
> will netwok all the machines for K12.  Will I be able to print my
> windows documents thru the server and do I also need win server
> software as well as K12? I will use the sever for the internet.  I
> plan to get one or two netwok printer to serve all my printing needs
> if that will work.  Feel free to answer all the question I dont even
> know I need to ask to get this started.  Thanks in advance for your
> help.
> In desperate straights
> Don Gould
> Hollandale Christian School

A problem is an opportunity.
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