Creating a school computer lab with edbuntu and ltsp
djgroos at gmail.com
Mon May 21 13:41:23 UTC 2012
Building on what Mike says, I first used Edubuntu 8.04 (Hardy) with thin clients. The clients were P3's @900 MHz (I believe was the speed--and 256-384 Megs RAM) and the server a Dual Core Xeon @ 2.0 GHz, I think, and with 3 Gig RAM and RAID 5. Things worked great until I used Flash or even worse, when I used a java-based app, "CmapTools". These apps quickly brought the server to a standstill--not acceptable.
The next year I upgraded from thin-clients to Local-apps, running Firefox and CmapTools as localapps and I was very satisfied with that, except I wanted to use some USB devices and there is some strangeness with what "local" means with local-apps. I believe I had upgraded some of my clients to P4's but things were mixed, but I had upgraded all clients to 512 Megs RAM.
The next year, I moved to fat clients so as to get that local support. I was able to upgrade all my clients to Pentium 4's, with 1 gig RAM. Over that year I found that I didn't want less than a P4 running @ 2.2 GHz. This was running Lucid. Things were great :)
This last school year I've not been in the classroom though am supporting 2 teachers who are using these systems and made no changes and all has gone well. Next year I expect I'll be running 12.04 again as fat clients. Since ALL processing is offloaded to the client machines, you no longer need server-level hardware, according to alkisg, and you simply use a dual-core desktop. He says in Greece the classroom computer labs use the teachers desktop as the fat-client server and that the clients use only 512 Megs RAM! Nice. If you want more detail on this perhaps he could tell you his setup though may already have it published somewhere.
Also, I remove Hard drives as well. I run up to 40 fatclients with a 2.8 GHz, 2, dual-core Xeon (4 cores) and 6 gigs ram and RAID 5. I have 2, 24 port, 10/100 duplex switches that have 2, 10/100/1000 server ports through which I daisy chain 1 switch to the other. The server uses the 2-nic setup.
On May 21, 2012, at 7:42 AM, Mike Biancaniello wrote:
> When a user logs in from a thin client, it is as if he/she is logging directly into the server. Any user accts/home dirs that exist on the server are accessed via thin client, so it never matters which client a student uses. You can lock down a good amount and you just do it on the server. The experience does not change from one thin client to another.
> All a thin client does is log into the server and act like a remote terminal. All applications run on the server, hence the very low requirements for the clients.
> Local apps allow spcified apps to run on the thin client, which increases the req specs for the clients, but offloads some load from the server. If you have clients that are more powerful, you can run those as 'fat clients' where almost everything runs on the client.
> As far as a processor, the bigger, the better.
> See the installation guide for server and client specs.
> Edubuntu 12.04 LTS Installation Guide
> Requirements and Preparation Installing Edubuntu is easy! We try our best to explain the installation process in a wa…
> Processor: Core 2 Duo or Core 2 Quad as recommended minimum. Simpler CPUs will work, but at a performance penalty.
> Memory: 512MB for the server itself, and between 256MB and 768MB of RAM per client, depending on the demands of the users. Typically, you would want at least 4GB RAM for 20 LTSP users, and ideally at least 8GB. Note that you can also use local applications (called local apps) to shed some memory usage to the thin clients.
> Disk: 20GB Depending on options. It's recommended that you keep the /home partition on fast disks for optimal performance, refer to the post-install section in this document for more information on setting up a home partition on RAID.
> Network: LTSP can be very demanding on local network resources. It is recommended that you have at least 1 gigabit connection to the server for every 15 thin clients, and at least 100mbit connections to the thin clients from your switches.
> From: Jeremy Schubert <jschubert at shaw.ca>
> To: Mike Biancaniello <mikebianc at aol.com>
> Cc: edubuntu-users <edubuntu-users at lists.ubuntu.com>
> Sent: Sunday, May 20, 2012 at 9:55 pm
> Subject: Re: Creating a school computer lab with edbuntu and ltsp
> Thanks for the info Mike, I will create a virtual machine edubuntu server to test this all out. But here are a few more initial questions fro you and everyone else. And I'd appreciate any documentation links.
> 1. Specs for the server? Assume it was hosting 30 thin clients.
> 2. I assume that when a client logs in from a machine, their profile (home?) is loaded onto the server so they can move from server to server. What is the best way of locking down settings per groups? (For example, what programs they can access, what happens when they surf the net, how much access they have to modifying desktops and backgrounds and if those modifications remain after logging out...)
> 3. Can I run batch scripts (or equivalents) to map home folders and other folders/directories for users to access?
> ----- Original Message -----
> From: "Mike Biancaniello" <mikebianc at aol.com>
> To: jschubert at shaw.ca, edubuntu-users at lists.ubuntu.com
> Sent: Sunday, May 20, 2012 5:55:27 PM
> Subject: RE: Creating a school computer lab with edbuntu and ltsp
> You really don't need all of the partitions. You can certainly create them in the install, though.
> Personally, I prefer to keep the stuff for which I need RAID to be off on its own server that just handles that and then use NFS to mount the shares (SMB if I must share to windows).
> Edubuntu can install the LTSP during the initial install.
> The standard install is to have 2 NICs on the server. One on the main ethernet (access to internet or other stuff like printers, shares, etc) and one to a private ethernet that hosts only the server and the ltsp clients.
> You can install the server with only a single NIC, but remember that it will answer DHCP requests for anything on that network, so if you have another dhcp server, you would have to edit the edubuntu dhcp config to only answer for the MAC addresses of the client PCs and ignore all others.
> The PXE clients don't need any operating system (mine don't even have hard drives), but you might need to edit the bios to ensure that the NIC is configured to boot "w/pxe."
> All of the clients will use the credentials on the edubuntu server to log in. You can, however, configure the server to use existing domain creds. I can't give you any info on setting that up, as I use kerberos in my house.
> I know that's kind of rambled, but hopefully it will help. I can always answer more pointed questions or clarify if requested.
> From : Jeremy Schubert <jschubert at shaw.ca>
> To : edubuntu-users <edubuntu-users at lists.ubuntu.com>
> Sent : Sunday, May 20, 2012 at 8:04 pm
> Subject : Creating a school computer lab with edbuntu and ltsp
> Hello there,
> I'm used stetting up school computer labs in the following fashion:
> 1. A group of client computers running windows xp or 7
> 2. A widows 2003 server with
> - 2 NICs
> - lots of ram
> - a system partition
> - a hidden partition for log files
> - a data partition for users
> - a partition for ISO files and programs that have to eunn from the server.
> 3. Workstations joined ro the domain forcing users ro login with domain credentials.
> 4. Roaming or
> mandatory profiles.
> 5. Group polocies to enforce certain settings
> I'd like to try the same thing with edbuntu and ltsp. So , basically, can I
> 1. Instal edbuntu on a box with lots of ram and partitions (raid5?)
> 2. Then install LTSI
> 3. Then star the work stations on PXE mode to connect to the server?
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