Introduction to AFS

Short words about your home directory

As you may have noticed, there are a couple of directories in your home directory that have been created to make it easier to protect and share files.

  • Public

    A place to put files that should be readable by anyone in the whole world. This includes .forward, .bashrc, .tcshrc, and similar files.

  • Private

    Files that should only be readable by the owner. This directory is not listable by anyone except the owner.

File system and storage

File systems and storage

AFS - Andrew File System

Your home-directory (ie. the directory pointed to by the $HOME variable) is placed on an AFS file system. This file system is backed up regularly.

Note that since ticket-forwarding to batch jobs does not work, the only AFS-access possible from batch jobs are to read files from your Public-directory which is world-wide readable (yes, the entire world). Use the parallel file system 'pfs' for data management in conjunction with batch jobs.

Using Environment Variables

Using Environment Variables

This page is assuming you use bash or another shell in the Bourne family of shells. Most of the informtation will be correct for other shells as well, but the examples cannot be assumed to be.

HPC2N recommends using bash, since it is the only shell that is fully supported by the batch system.

Environment variables are a set of dynamic named values, generally meant to make your life easier. Some are built-in, some are set by loading various modules, and you can also define extra to help yourself.

Environment Variables

Environment Variables

There are many environment variables. Some will be set automatically at login and some which you can change if needed. Many of the environment variables will be related to paths and storage locations, but there are also some which are set for specific applications (like compilers). These environment variables willl be set when you load the 'module' for the application in question. (Read more about modules in the section about them.)

HPC2N environment

HPC2N environment

The contents of your home directory are placed on an AFS name space and is backed up regularly. AFS (Andrew File System) is a distributed networked file system, which was developed for security and scalability. Read more about AFS here.

Most differences between AFS and traditional networked file systems (like NFS) are transparant for the user, but some important differences are:


Updated: 2017-09-21, 11:05