AFS

About

AFS (the Andrew File System) is a distributed, client-server, file system used to provide most file-sharing services in SCS. An AFS client is installed by default on Facilitized Unix, and Windows hosts. Some properties of AFS are that it:

• Provides transparent access to files. Files in AFS may be located on different servers, but are accessed the same way as files on your local disk regardless of which server they are on.
• Provides a uniform namespace. A file's pathname is exactly the same from any Unix host that you access it from.
• Provides secure, fine-grained access control for files. You can control exactly which users have access to your files and the rights that each one has.

Some AFS concepts

Cells. AFS, at the top level, is organized into cells, which correspond to separate administrative groups. The cs.cmu.edu cell is administered by SCS Facilities, and there are other AFS cells on campus. Details.

Volumes & quotas. Related directories in AFS are organized into units called volumes. For example, your home directory in AFS will be in its own volume. Each volume has its own quota that determines how much disk space it can use. Details.

File protections and ACLs. AFS does not use standard Unix permissions to protect files. Instead, it attaches an access control list (ACL) to each directory (not each file) in AFS, and controls most access according to the contents of that ACL. Details.

Authentication. Within SCS, AFS access is based on limited-lifetime tokens that you get when you run kinit or login using your SCS Kerberos password. Details.

Backups & restores

SCS automatically backs up most volumes in AFS. See the section on AFS backups for details.

How to

Additional information

The following off-site links will open in a new browser window:

http://www.openafs.org

The home of the OpenAFS project, including AFS downloads and detailed documentation on all aspects of AFS.