Since the Lenny version of -Debian Edu / Skolelinux, a -feature to save power have been included. It is as simple as it is -practical: Shut down unused clients at night, and turn them on again -in the morning. This is done using the -shutdown-at-night Debian package.
- -To enable this feature on a client, the machine need to be added to -the netgroup shutdown-at-night-hosts. For Debian Edu, This is done in -LDAP, and once this is in place, the machine in question will check -every hour from 16:00 until 06:00 to see if the machine is unused, and -shut it down if it is. If the hardware in question is supported by -the -nvram-wakeup -package, the BIOS is told to turn the machine back on around 07:00 +- -10 minutes. If this isn't working, one can configure wake-on-lan to -try to turn on the client. The wake-on-lan option is only documented -and not enabled by default in Debian Edu.
- -It is important to not turn all machines on at once, as this can -blow a fuse if several computers are connected to the same fuse like -the common setup for a classroom. The nvram-wakeup method only work -for machines with a functioning hardware/BIOS clock. I've seen old -machines where the BIOS battery were dead and the hardware clock were -starting from 0 (or was it 1990?) every boot. If you have one of -those, you have to turn on the computer manually.
- -The shutdown-at-night package is completely self contained, and can -also be used outside the Debian Edu environment. For those without a -central LDAP server with netgroups, one can instead touch the file -/etc/shutdown-at-night/shutdown-at-night to enable it. -Perhaps you too can use it to save some power?
+ +It take all kind of contributions to create a Linux distribution +like Debian Edu / Skolelinux, +and this time I lend the ear to Justin B. Rye, who is listed as a big +contributor to the +Debian +Edu Squeeze release manual. + +
Who are you, and how do you spend your days?
+ +I'm a 44-year-old linguistics graduate living in Edinburgh who has +occasionally been employed as a sysadmin.
+ +How did you get in contact with the Skolelinux/Debian Edu +project?
+ +I'm neither a developer nor a Skolelinux/Debian Edu user! The only +reason my name's in the credits for the documentation is that I hang +around on debian-l10n-english waiting for people to mention things +they'd like a native English speaker to proofread... So I did a sweep +through the wiki for typos and Norglish and inconsistent spellings of +"localisation".
+ +What do you see as the advantages of Skolelinux/Debian +Edu?
+ +What do you see as the disadvantages of Skolelinux/Debian +Edu?
+ +These questions are too hard for me - I don't use it! In fact I +had hardly any contact with I.T. until long after I'd got out of the +education system.
+ +I can tell you the advantages of Debian for me though: it soaks up +as much of my free time as I want and no more, and lets me do +everything I want a computer for without ever forcing me to spend +money on the latest hardware.
+ +Which free software do you use daily?
+ +I've been using Debian since Rex; popularity-contest says the +software that I use most is xinit, xterm, and xulrunner (in other +words, I use a distinctly retro sort of desktop).
+ +Which strategy do you believe is the right one to use to +get schools to use free software?
+ +Well, I don't know. I suppose I'd be inclined to try reasoning +with the people who make the decisions, but obviously if that worked +you would hardly need a strategy.
I am happy to announce that finally we managed today to wrap up and -publish the third beta version of -Debian Edu / Skolelinux based -on Squeeze. If you want to test a LDAP backed Kerberos server with -out of the box PXE configuration for running diskless machines and -installing new machines, check it out. If you need a software -solution for your school, check it out too. The full announcement is -available -on the project announcement list.
- -I am very happy to report these changes and improvements since -beta2 (there are more, see announcement for full list):
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- It is now possible to change the pre-configured IP subnet from - 10.0.0.0/8 to something else by using the subnet-change tool after - the installation. - -
- Too full partitions are now automatically extended on the Main - Server, based on the rules specified in /etc/fsautoresizetab. - -
- The CUPS queues are now automatically flushed every night, and all - disabled queues are restarted every hour. This should cut down on - the amount of manual administration needed for printers. - -
- The set of initial users have been changed. Now a personal user - for the local system administrator is created during installation - instead of the previously created localadmin and super-admin users, - and this user is granted administrative privileges using group - membership. This reduces the number of passwords one need to keep - up to date on the system. - -
The new main server seem to work so well that I am testing it as my -private DNS/LDAP/Kerberos/PXE/LTSP server at home. I will use it look -for issues we could fix to polish Debian Edu even further before the -final Squeeze release is published.
- -Next weekend the project organise a -developer -gathering in Oslo. We will continue the work on the Squeeze -version, and start initial planning for the Wheezy version. Perhaps I -will see you there?
+ +Recently I have spent time with +Skolelinux Drift AS on speeding +up a Debian Edu / Skolelinux +Lenny installation using LTSP diskless workstations, and in the +process I discovered something very surprising. The reason the KDE +menu was responding slow when using it for the first time, was mostly +due to the way KDE find application icons. I discovered that showing +the Multimedia menu would cause more than 20 000 IP packages to be +passed between the LTSP client and the NFS server. Most of these were + +NFS LOOKUP calls, resulting in a NFS3ERR_NOENT response. Because the +ping times between the client and the server were in the range 2-20 +ms, the menus would be very slow. Looking at the strace of kicker in +Lenny (or plasma-desktop i Squeeze - same problem there), I see that +the source of these NFS calls are access(2) system calls for +non-existing files. KDE can do hundreds of access(2) calls to find +one icon file. In my example, just finding the mplayer icon required +around 230 access(2) calls.
+ +The KDE code seem to search for icons using a list of icon +directories, and the list of possible directories is large. In +(almost) each directory, it look for files ending in .png, .svgz, .svg +and .xpm. The result is a very slow KDE menu when /usr/ is NFS +mounted. Showing a single sub menu may result in thousands of NFS +requests. I am not the first one to discover this. I found a +KDE bug report +from 2009 about this problem, and it is still unsolved.
+ +My solution to speed up the KDE menu was to create a package +kde-icon-cache that upon installation will look at all .desktop files +used to generate the KDE menu, find their icons, search the icon paths +for the file that KDE will end up finding at run time, and copying the +icon file to /var/lib/kde-icon-cache/. Finally, I add symlinks to +these icon files in one of the first directories where KDE will look +for them. This cut down the number of file accesses required to find +one icon from several hundred to less than 5, and make the KDE menu +almost instantaneous. I'm not quite sure where to make the package +publicly available, so for now it is only available on request.
+ +The bug report mention that this do not only affect the KDE menu +and icon handling, but also the login process. Not quite sure how to +speed up that part without replacing NFS with for example NBD, and +that is not really an option at the moment.
+ +If you got feedback on this issue, please let us know on debian-edu +(at) lists.debian.org.