Leopard Server in educational setting

Question

I currently have a panther server which is going to be replaced by a new snow leopard server. My current server has two HDs that are mirrored. All students (380 kids in the school) are authenticated and save to their home directories on this server. They can then use laptops, computers in the lab and other rooms to easily access their data. It has worked FLAWLESSLY for the last 5 years.
Now, the new server is MUCH more powerful, comes with 3 HD (1 for system, 1 for data, 1 for backup using retrospect) and has a lot more RAM than my current Panther machine. I am told that it will be setup so students will save to their client machine, have a mobile account where the data will be transferred or synced.
After doing some research on this I came upon John Welsh's article that he wrote on Oct 16, 2009 where he gave a favorable recommendation to the 10.6 server and talked about login and logout syncing.
So, here is my question. When I have a class of 30 kids all logging out at one time, saving their documents, and then having the server sync all of them to their home directories at the same time, is this more efficient than having them save directly to the server (I have no applications running on the server, these are installed on the clients throughout the building) at different times during the period? For example, if I have a class of kids working on a Word project chances are they will be saving at different times and thereby hitting the server in small increments instead of all at one time when the period ends. Also, when logging out it would seem to be a lot less effort for the server just to deauthenticate them rather than having to save everything they have done to their home directory.
Perhaps a business server should be set up differently than a school since I doubt everyone in an office, even if you had 30 people in the office would be logging out at exactly the same time like a classroom of 30 kids.
Question is then what do some of you feel is the best way to setup an OSX 10.6 server for a school of 400 kids. The kids have access to the lab which will have 30 new imacs, a classroom set of computer (emacs running Tiger) and a set of laptops running 10.5.
I don't want real intricate details but some overall guidelines. Oh, I have 1000 mb/s routers and switches.
Also, as as sidelight, is there anything wrong with mirrored HDs? If one goes bad the other takes over immediately. If a Panther server could do this, wouldn't this be okay for a snow leopard server?
Thanks for any advice you can offer.
Bob Barr

Answer 1

Hi Bob
You've had no takers so far so here's my tuppenceworth:
+"is there anything wrong with mirrored HDs?"+
No not really. Bear in mind a RAID Mirror is not a backup.
+"If one goes bad the other takes over immediately?"+
If you want to put it that way. The secondary mirror is an exact 'copy' of the primary. If the primary fails the mirror takes over (with little or no perceived downtime). Mirrors are generally considered 'slower' than Stripes. Two writes instead of one. But that's the price you pay for redundancy. What plans have you made if both drives fail? Consider the worst possible scenario and depending on budget plan for it.
+"If a Panther server could do this, wouldn't this be okay for a snow leopard server?"+
Yes. Software RAID is also available in the client OS.
If I've understood your post correctly the XServe is populated with 3 drives? Have you considered Apple's Hardware RAID Card? This would offer Performance and Redundancy - RAID 5. You would still need a backup strategy/plan.
In an environment like yours - generally - I would mirror the drive used for data and install the OS on the other drive. Apart from the system don't store anything else of importance on it. You could compliment this with an externally attached firewire drive (or two) if you wish? One as a nightly or weekly or monthly scheduled clone/backup of the Server OS itself and similarly one for the Data. That way if the Server drive goes down Student Data is not affected. Replacing the Drive and getting the server up and running again should not take too long if that happens.
Depending on how many simultaneous logins you're trying to provide for then you may want to consider Replicas for load balancing purposes? is it safe to assume 380 kids = 380 workstations?
Educational needs in general are different to Business ones. Based on what you're saying it makes no sense (for me) to cache student profiles locally - unless it's for performance reasons? If Students are not going to be impacting the network bandwidth with video editing/rendering etc leave their profiles on the server. Management in many ways is simpler/easier that way. Yes multiple simultaneous syncing at log out does/will have an impact on the network as a whole although you can control what gets synced. There's no need to sync everything.
Another way of doing this is to have students log in locally with a standard 'generic' student account. They work as normal and save/upload their data to their Server-based home folder. Access to the parent folder housing student homes can be defined as an auto-mounting share point via a Computer Group MCX. Students will 'see' everyone else's home folder but will have no access to them other than their own.
There are still further ways of doing this depending on the environment? For example AD-OD Integrated environments and dual homes?
Ultimately it will depend on what you want to achieve? AFAICS there's no reason you can't have with 10.6 what you have with 10.3? If it's been working flawlessly for the last 5 years and provided you've prepared the ground properly first, it should continue in the same way for the next 5?
HTH?
Tony