Niksula disk usage howto

Introdution

Niksula has a long history in providing a more or less relaxed computing environment for computer science students. There haven't been too many rules as everybody has used their common sense.

As everybody probably has guessed there is only a limited amount of disk and backup tapes in Niksula. Currently the limiting factor is the backup resources. So to avoid wasting them the administrators have place a 1000 MB pseudo-quota for all Niksula users.

This pseudo-quota is checked only occasionally (when we are feeling very BOFHy, or disks/backup tapes are full). If you happen to be using too much disk space a nice little message is sent to you. If you happen to be using way too much disk space you are entitled for a warning. After a few warnings or several nice little messages your account will be closed (shell changed to /c/bin/overquota) and your files will be moved to a nice little location called /dev/null.

Basic rules

  1. If you happen to study the art of MP3 encoding or decoding, please store all your material in /p/scratch.
  2. If you happen to study the art of file transfer, please remove your test material after your experiment.
  3. If you happen to study the art of anatomy, please store all your material in /p/scratch and practise the art of file transfer.
  4. If you have installed a fine piece of software that might be useful for others, please move the installation to /p/contrib.
  5. If you happen to study the black art of software piracy, please store all your illegal files somewhere else. Software piracy is a crime, and is strictly forbidden in Niksula.
  6. If you really do need over 1000 MB for your CS- studies, please mail guru@niksula.hut.fi and the administrators will arrange some project space for you. You shouldn't consume over 1000 megabytes for a long time (long time << 7 days).
  7. If you use over 1000 MB and don't tell a very good reason when asked for it, the administration can't guarantee the integrity and availability of your data. The administrators have acquired the knowledge of the magical spell "rm".

Where to store my temporary files?

When running large batch jobs, lots of data can be created and needed for a short time. If possible the temporary data should not be stored in your home directory. Please remove the temporary data as soon as possible! If the home directory filesystem is filled up Niksula simply doesn't work.

Here are some places where you can store your files in Niksula:

Your home directory, ~, $HOME
A place where NO temporary data should be stored! This file system is backed up every night. You could store the final reports here.
Scratch, /p/scratch, /p/scratch/`whoami`
Data stored on this file system is deleted after three (3) days. The free disk space is dependant on other Niksula users. No backups are taken but the file system is built on a RAID5 disk system. So in case any data is lost, please look in the mirror.
/var/tmp
This directory lies on the local workstation and is thus probably faster than the network filesystems. A good place for files under 0.5 GB. No backups are taken and the data lies on a single disk and can be lost in a disk crash or if the workstation is reinstalled.
/tmp
This filesystem or directory lies either in the virtual memory (Solaris) or on the local disk (FreeBSD). Please store only small files (<10 MB) here. The contents are lost every time the workstation is rebooted.
/u/projects/
This filesystem exists to serve the needs of any kind of projects. It is a network file system which is backed up every night. Please mail guru@niksula.hut.fi and a project directory should be created for you.

Useful commands

du

You can use the Unix command "du -sk" to find out your disk usage in kilobytes. For more information on "du", please try running "man du".

For a more detailed view of your disk usage, try the command "du -sk  .[^.]* * | sort -n". This will run du to all files and dot files on the directory and sort the outcome, so you can easily find the most disk space consuming files and directories.

One thing about du and networked file systems: du consumes lots of resources, so please avoid running it just for the fun.

locate

You can use locate to search for files in Niksula. Usage is quite simple: locate filename. There has been problems with the locate databases in Niksula so it might be possible that the command simply doesn't work.

FAQs

My scratch has been cleared on some Solaris machines?
At the moment there are two scratch file systems on some Sun Solaris workstations: /p/scratch and /p/scratch.old. The latter one is going to be removed some time in the future.
Why doesn't mkscratch work?
The administrators create the scratch directories for everybody.
Why can't I find the scratch directory in my homedirectory?
Say: ln -s /p/scratch/`whoami` scratch
Why doesn't my scratch directory exist?
The administrators haven't created one for you. Please mail guru@niksula.hut.fi.
I have installed software X in my home directory because I don't have write permissions to /p/contrib.
Please mail guru@niksula.hut.fi and tell what kind of software you were planning to install and we'll probably grant you access to /p/contrib.
This page was last updated on September 12th 2007 by the feared URUG of Niksula.