There are different ways of setting up a Skolelinux solution. It can be installed on just one standalone PC or a regional wide solution at many schools operated centrally. This variety of configurations makes a huge difference on how things are set up regarding network components, servers and client machines.
The purpose of the different profiles is explained in the network architecture chapter.
- The computers running Debian Edu / Skolelinux must have either i386, amd64 or powerpc processors.
- On powerpc, the installation media will only boot on machines of the newworld sub-architecture, which are the systems from Apple with a translucent case.
- Thin client servers need two network cards when using the default network architecture:
- eth0 is connected to the main network (10.0.2.0/23),
- eth1 is used for serving the thin-clients (192.168.0.0/24) .
- Consider 2 GB RAM for 30 clients and 4 GB RAM for 50-60 clients.
- Disk space requirements depend on profiles used, but any disk larger than 10 GiB will be sufficient for a workstation or standalone installation, 15 Gib for a thin-client server and at least 30 GiB on the main server. As usual with disk space on a main-server: the bigger the better.
- Thin clients can run on as low as 64 MiB RAM and 133 MHz processor, though 128 MiB RAM and somewhat faster processors are recommended.
For running Iceweasel/Firefox and OpenOffice.org, 128 MiB RAM is a minimum requirement.
- For workstations, diskless workstations and standalone PCs 800 MHz, 256 MiB RAM are minimum requirements, though 512 or 1024 MiB RAM will perform considerable better. Just a faster CPU will speed things up.
Swapping over the network is automatically enabled, the swap size is 32 MiB, if you need more you can tune this by editing /etc/ltsp/nbdswapd.conf on tjener to set the SIZE variable. Please tune up the swap size either locally on the pc or on the server.
- If your diskless workstations have harddrives, it is recommended to use them for swap as it is a lot faster than network swapping.
On workstations with little RAM the spell checker can cause OpenOffice.org to hang if the swap space is too small. Then the system administrator has to disable the spell checker on OpenOffice.org or students have to kill OpenOffice.org, resulting in loss of work. Enabling at least 512 MiB swap on a 256 MiB RAM workstation solves this, and the spell checker runs smoothly.
- Laptops have the same requirements as for workstations since they are just movable workstations.
Hardware known to work
A list of tested hardware is provided from http://wiki.debian.org/DebianEdu/Hardware/ . This list is not nearly complete
http://wiki.debian.org/InstallingDebianOn is an effort to document how to install, configure and use Debian on some specific hardware. Therefore potential buyers would know if that hardware is supported and owner would know how get the best out of that hardware.
An excellent database about hardware supported by Debian is online at http://kmuto.jp/debian/hcl/.
Requirements for a network setup
When using the default network architecture, these rules apply:
- you need exactly one main server, the tjener
- you can have up to 50 (diskless) workstations on the main network
- you can have up to 20 ltspservers on the main network
- you can have hundreds of thin clients and/or diskless workstations on each ltspserver network
- you can have hundreds of other machines which will have dynamic IP addresses assigned
- for having access to the internet you need a router/gateway (see below)
A router/gateway, connected to the internet on the external interface and running on the IP address 10.0.2.1 with netmask 255.255.254.0 on the internal interface, is needed to connect to the internet.
The router should not run a DHCP server, it can run a DNS server, though this is not needed and will not be used. (If the router runs a DHCP server you must disable the DHCP server on the main server and you will loose some features and certain documented procedures will work differently. So better disable the DHCP server on the router.)
If you are looking for a i386 based solution (so that you can reuse an old PC), we recommend IPCop or floppyfw.
If you need something for an embedded router or accesspoint we recommend using OpenWRT, though of course you can also use the original firmware. Using the original firmware is easier, using OpenWRT gives you more choices and control. Check the OpenWRT webpages for a list of supported hardware.
It is possible to use a different network setup, this is the documented procedure to do this. If you are not forced to do this by an existing network infrastructure, we recommend against doing so and recommend you stay with the default network architecture.