AFS volumes & quotasAn AFS "volume" contains a subtree of related files and directories descending from a "mount points" that specifies where in the AFS directory tree the volume resides. For example, files for a typical SCS user named bovik would be contained in a dedicated volume called user.bovik and mounted at /afs/cs.cmu.edu/user/bovik.
Types of volumesSCS supports four main types of AFS volumes:
- User volumes: Every SCS user has a volume located under /afs/cs.cmu.edu/user/<user_ID>
- 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 are used for Unix software collections
Read-only & read-write volumesTo increase availability in case an AFS server fails, some software (in particular important system software and misc collections) located under /afs/cs.cmu.edu/ is replicated across several file servers. The 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 read/write contents are automatically released (copied) to the read-only volumes.
QuotasEach volume in AFS, including that containing your user files, has an associated quota:
- The default user-volume quota is 1 GB for new accounts. The maximum user-volume quota is 10 GB.
- The maximum academic-volume quota is the maximum volume size, 25 GB
- The maximum project-volume (misc collection) quota is the maximum project-space allocation, 25 GB.
If you require additional space, please contact the SCS Help Desk at <email@example.com> or x8-4231. If you are using an application that attempts to write to a full volume, the write may fail and data, such as changes to a file you are editing, may be lost. You can use the fs command to see how much free quota remains in a volume.
Determine quota useThe 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