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Re: [K12OSN] Thoughts for my upgrade...



One simple alternative you might consider for your load-balancing/failover is 
 using the failover package (http://failover.othello.ch).  In the case of two 
machines, they each have their own hardcoded address, and then a third 
address "floats" between them in that it's up on the first machine, but if 
that machine fails, the second machine binds the floating address and takes 
over.  If you use two floating addresses, one normally assigned to each box, 
and then round-robin DNS, you can have your load-balancing, and if one of the 
boxes fails, the failover package on the other will pick up the floating 
address from it.  So, your users might see a performance hit, depending on 
the load and number of users on the box, but at least they won't have to 
reboot and try again.  I use failover on a pair of boxes acting as print 
server and it works great.  Easy to install and configure too.  If you want 
to use more than two boxes, you could either arrange the failover in pairs, 
or just have each box be responsible for the box on 'its left', with the last 
box being responsible for the first box (hope that makes sense).

Petre

>
> Terminals would connect to SVHSAPP.silvervalley.k12.ca.us, which would
> resolve to the different appservers via round-robin DNS. This provides some
> rudimentary load balancing, and eliminates one step in our current login
> process, using the chooser screen to pick a server. Obvious downside is
> that if one server goes down, every n'th terminal will be forced to reboot
> to try to get to a different server, at least until I can modify the DNS or
> fix the server. I had been considering mosix, but the majority of our users
> will be using Mozilla and OpenOffice most of the time, and since those
> don't migrate, we wouldn't see much balancing.
>
> 100GB is far too large for our tape system to handle well, so I'm
> considering putting together a backup server in another building that's
> about 150 yards away, but connected by fiber. I'd use rsync to back up
> SVHSAPP01 - an interesting sample script on rsync.org shows how to do
> incrementals as well as fulls, so that if a teacher or student comes to me
> saying they loast a file 3 days ago, I'd still be able to recover it. Using
> one of our old app servers and buying a large harddrive for it makes this
> much more economical than upgrading to tape robots and such :)
>
> I apologize for taking up so much bandwidth - writing this stuff down helps
> me think it through, and if I missed anything dumb, someone here will catch
> it. And hopefully, it'll help someone else doing a large installation -
> these 6 servers support 140 terminals spread all over our high school
> campus.





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