Isis AFS Space

Using AFS space on the campus servers

Reviewed by Bil Hays 5/2/2014

The campus support group, ITS, provides AFS home directory space, and it is possible for you to use this space to supplement your Computer Science AFS home directory space.  Faculty and grad students have a 250 MB quota on the campus AFS server, isis.unc.edu.  To use this space, you will first need to obtain a login on the campus systems. See here for info on getting a campus login.  Once you have obtained a campus login (or “Onyen”), you can save files there, and you can access the files through your Comp Sci account.

Changing files and directories on your campus account requires that you have an AFS token on the campus systems.  The rest of this article describes how to get to isis space from Comp Sci systems, how to set permissions so others can access this space, how to use links to access this space relatively seamlessly, and possible uses for this space.

Getting to isis space from Comp Sci systems

Home directories on the campus server, isis, have paths like the following, for a user named “example”:

/afs/isis.unc.edu/home/e/x/example

The path consists of /afs/isis.unc.edu/home/, followed by a directory with the first letter (“e”) of the login, followed by a directory with the second letter (“x”) of the login, followed by the login.  When logged in to a Comp Sci UNIX system, you can figure out the directory path and “cd” to this directory, or you can log in to isis.unc.edu and execute “pwd” to find out the path.  As mentioned above, to access this space from a Comp Sci system, you’ll need an AFS token for isis. To get this, type:

klog onyen -cell isis.unc.edu

where “onyen” is your campus login (Onyen). You’ll be prompted for your campus password.

Setting permissions so others can access your isis space

For folks on Comp Sci systems to access files in your isis space, they will need to have read permission on your isis home directory.  Since we are in a different AFS cell, you’ll need to turn on read permissions for all users on the uppermost level of your isis home directory. For example

fs setacl /afs/isis.unc.edu/home/e/x/example system:anyuser r

You might want to create a subdirectory in which you keep public files that others can both read and list:

mkdir /afs/isis.unc.edu/home/e/x/example/public
fs setacl /afs/isis.unc.edu/home/e/x/example/public system:anyuser rl

See  AFS file security for more info on setting AFS file and directory permisions.

Using links to access your isis space

If you want to be able to access your isis space without having to remember the path, you can set up a link pointing to your isis space:

cd
ln -s /afs/isis.unc.edu/home/e/x/example isis-space

This makes a link called “isis-space” in your home directory, pointing to the isis home directory of user “example”.

Uses for isis home directory space

You can use this space as you wish.  The space itself is unlikely to be of much use for storage, since it does not amount to much.  However, the isis home directory is used by several of the campus research compute servers, so if you use these services you may want to customize your isis home directory.  In addition, the space may be useful for setting up or testing an alternative web space.