[YLUG] Server purchase

[Arthur Clune]

On 19 May 2006, at 11:14, Richard G. Clegg wrote:

> 1) Some kind and lovely person from a different dept is going to  
> buy us a shiny new server and I've no real idea what I am looking for.

We use the new Sun Opteron servers. A single opteron 1U box is very  
cheap (about 6-700 quid). Goes like stink as well.

>  I've had a brief scout and the hardware RAID I could see involved  
> stupidly expensive SCSI disks -- is this unavoidable?

You could go SATA instead.


> 2) The idea at the moment seems to be to have two machines, a main  
> machine and a backup and to use a virtual IP address, IP chains and  
> heartbeat to get the machines to switch over on failure.

UltraMonkey is what you want for this bit of it. http:// 
www.ultramonkey.org


Thing is, what are you covering yourself against here? You have two  
different ways of ensuring redundancy and seem to want both.

Option 1) Reliable servers: mirror'd raid, dual psu etc etc.
Option 2) Shonky servers but load balanced.

There's another option; put the db on a single reliable server class  
machine and run the web stuff on some shonky hardware but load  
balance it (this assumes your app will work in this setup of course).  
For dr purposes you should replicate the db onto something else, but  
that can be cheap as well since it'd only be used in extremis.

UPS for the db server + one of the web servers and you'd be good to  
go. It wouldn't be totally 100%, but it'd cover most eventualities  
(the main failure mode would be a power cut if you were running on  
the non-ups'd web server only). Adding a bit more ups would solve  
that, and it's something that could be done either now or later.

Arthur

-- 
Dr. A. Clune, Systems Security Advisor
The  Computing Service,  University of York
ajc22 at york.ac.uk   01904 433129