AFS Project Space

This document discusses project management in AFS and project storage space in /p. The first part of this document provides a broad overview of project storage management in AFS. The second part demonstrates the afsdf tool used for project space information.

AFS and Projects

The /p directory structure provides a location for research project storage space in AFS. A directory per project is found under /p. On local workstations, /p is a link to /afs/cs.wisc.edu/p in the Computer Sciences Department AFS cell.

Requesting storage in AFS is a three step process: rent storage, request a project, request additional volumes.

Renting storage

To request a project in AFS, the project owner must first rent storage space in AFS. AFS project storage is rented in 5GB increments using the CS department web forms. There is currently no charge for rented space on a per-semester basis.

Requesting a project

Once AFS storage is rented, a project can be requested using the web forms. This creates a directory under /p where the project’s files are accessed. Newly-created projects contain a public and private directory along with an AFS group to allow other project users to manipulate ACLs within these directories. Multiple projects can be requested under a single rented storage space. A user can also request several rental pools to separate billing for different projects if necessary.

Requesting additional volumes

After a project is created, additional AFS volumes can be requested via the web forms to provide storage space. Each AFS volume is mounted as a directory, A maximum quota is specified when the volume is requested. If necessary, the quota can be changed later using the web forms.

The maximum quota for an AFS volume is 32GB. The recommended large volume and maximum backed up size is 5GB. Each AFS volume has a copy on write snapshot created at midnight each day. All volumes with quotas equal to or less than 5GB are backed up nightly. The Systems Lab recommends that volume size be kept under 1000 MB for performance and management reasons. Multiple large volumes can be requested and mounted within each other to accomodate a complex directory hierarchy and/or large storage. Please keep in mind that only the data stored, not the volume quota, counts against the amount rented.

The volume quotas are a hard limit. That is, once you reach this quota, you will not be able to write additional data to this volume. The storage rental is a soft quota. When the sum total of the stored data exceeds the amount you have rented, you will receive email from the CSL informing you of this situation and requesting that you rent additional storage space. The reason for the soft limit is so that a project isn’t prevented from doing work while additional space is rented or unused data is removed.

Tools

The afsdf command provides information on project storage usage in AFS, similar to the unix df command. man afsdf contains additional information about the flags for this command. As an example:

% afsdf bucky

This shows that user bucky has rented 25GB of storage in AFS. Of that, 3GB is currently unused.

% afsdf -V bucky

This example shows the usage for each volume. The disk usage in this view is updated nightly. This shows that the usage total for all volumes is 21GB. The total quota for all volumes is 32GB.