Volumes & quotas

About

An AFS volume is a container for a subtree of related files and directories. Volumes are attached to mount points, which tell AFS where a volume is located in the AFS directory tree. For example, a typical SCS user named bovik would be contained in its own AFS volume called user.bovik, which would be mounted at /afs/cs.cmu.edu/user/bovik.

Types of volumes

In SCS, there are four main types of AFS volumes:

User volumes. Every SCS user has a volume located under /afs/cs.cmu.edu/user/<username>.
Academic volumes. Instructors teaching graduate courses in SCS can request academic volumes under /afs/cs.cmu.edu/academic.
Project volumes. Individuals and research projects may request project volumes under /afs/cs.cmu.edu/project/.
Misc collection volumes. These volumes are used for Unix software collections.

Read-only & read-write volumes

In order to increase availability in case an AFS server goes down, some software (in particular important system software and misc collections) located under /afs/cs.cmu.edu/ is replicated across several file servers. These replicated copies are read-only (they cannot be modified). The corresponding read/write volume is located under /afs/.cs.cmu.edu (note the "." in front of cs.cmu.edu). Every night, the contents of the read/write volume are automatically released to the read-only volumes. Misc maintainers can also use Jeeves to manually release volumes.

Quotas

Each volume in AFS, including the volume that contains your user files, has a quota associated with it.

User volume quota is 1 GB for new accounts.
Older user accounts may use Jeeves to increase their volume quota to 1 GB.
If more space is required, contact help+@cs.cmu.edu.
Academic volume quota may be up to the maximum volume size of 25 GB.
Project volume quota may be up to the maximum volume size of 25 GB.

If you are using an application that attempts to write to a volume that is full, it is possible that the write might fail and data, such as changes to a file you are editing, might be lost. You can use the fs command to see how much free quota is left in a volume, and Jeeves to change your AFS quota yourself, without having to contact Facilities.

How to use the fs command to determine quota use

The fs command is in /usr/local/bin on Facilitized Unix systems. The following commands will show current quota use for a volume:

fs lq <directory-name>

will list the quota information for the given directory. For example:

 % fs lq /afs/cs/user/bovik
  Volume Name                   Quota      Used %Used   Partition
  user.bovik                    50000     42766   86%         59%

fs lv -dir <directory-name>

will list the current status of the named directory. The available remaining quota is the difference between the maximum quota and the number of blocks used. For example:

 % fs lv /afs/cs/user/bovik
 Volume status for vid = 25836 named user.bovik
 Current disk quota is 50000
 Current blocks used are 42766
 The partition has 7023124 blocks available out of 17212287

How to use Jeeves to change AFS quotas

Jeeves is a telnet-based service that can be used to change AFS quotas and perform other AFS-related tasks. See the Jeeves documentation for details on how to connect to Jeeves and a list of all commands.

You can connect to Jeeves by telneting to jeeves.srv.cs.cmu.edu using a Kerberized telnet client, such as NiftyTelnet on a Windows PC, or the standard telnet client on Facilitized Unix hosts. Once connected, you will be presented with a menu-based interface. To change your AFS user quota, perform the following steps after you have connected:

Type "afs" to go to the AFS-related operations sub-menu.
Type "quota" to go to the AFS quota operations sub-menu.
Type "change" to change your AFS quota.
You will be asked for the name for the volume. Type user.your-username, for example "user.bovik" if your username is "bovik".
You will be asked for a new quota. Type the amount of quota in kilobytes that you want. For example, "50000" if you want to change your quota to 50 MB. The maximum Facilities-provided quota for AFS user volumes is 1GB.

Project volume administrators and misc collection maintainers can also change quotas for the volumes that they administer. See the Jeeves documentation for details.

An AFS volume resides on a single disk partition. If you ask for more additional quota than there is remaining space on the partition in which the volume is located, Jeeves will automatically move it to a partition with more space. Please do not increase your AFS quota to the maximum permitted if you do not need that space. We do not have enough free disk space on-line at any one time for everyone to do so.