Re: [sheflug] Assessing server requirements

[Gary Stimson <bulk [at] xxxxxxxxxxxxxx>]

Hi David

David Willington wrote:
> Dear All
> 
> I need to work out a specification for a production server. Can anyone
> point me in the right direction for methods to work out what I need?
> It'll be a LAMP server running moodle for a school of about 1600 users

Some things to consider, in no particular order:

In terms of methods, I think you're trying to determine how much
processing power etc is required? You didn't say how many of those 1600
users will be using the server during any period. I'm guessing around
100 max? Of those, you'll get a few short load spikes while each class
starts up the application and then each individual user will probably
only be making demands of the server for a small percentage of the time?
You don't need a particularly powerful server for this by today's
processor standards.

At the moment, we put Pentium D 930 3.0 dual core chips in the rack
servers we specify because they have performance rivalling a dual Xeon
system for a fraction of the cost and power consumption. The chips are
about £116 from distributors. The 3.0 chips have max power consumption
of 95W; for 3.2GHz+ it's 130W.

If the school would prefer a quiet/low power consumption/lowish cost
server then consider using a system based around the new Intel Core
Solo/Duo chips. If physical space is an issue, a pentium-4 system on a

Use at least 2 disks in RAID 1 mirror or 3 disks in RAID 5 to protect
data in case of disk failure. If you want to use the server as a general
filestore server also (which will make little demand of the processor)
then it's a good idea to have the database partition on separate disks
for speed.

Speaking of RAID, don't bother with on-board ICH5R etc motherboard RAID
because you're generally better off with linux software RAID. If you
want hardware RAID then 3ware cards rock but are overkill unless the
disks are going to be in heavy use.

Are you supporting this hardware? If so then it's wise to have the
server email you in the event of disk failure (look at mdadm if using
software raid) etc.

After disks, the next biggest causes of server failure are failed fans
and PSUs. If you are supporting the hardware, consider using lm_sensors
to monitor fan speeds and CPU/case temperatures and alert you where
necessary. Therefore check the motherboard is lm_sensors compatible.

I'm sure you've remembered to think about backups. :-)

HTH

Gary



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