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Group accounts & shared diskspace

A "Group Account" is the way we allow groups of people to share files in ENCS; it supplies a "group directory", or "group folder". Group Accounts can be issued for academic purposes (teaching or research), or for administrative purposes. The Group Account is revoked once the mission of the group has come to an end (for example, when the course for that group finishes).

A request for a Group Account must come from a full time employee. When requesting a Group Account (by e-mail to servicedesk@encs.concordia.ca), please explain the group's purpose, and give us the ENCS usernames (or Concordia student ID numbers) of the proposed group members.

The main features of a Group Account are:

Shared file space for group members

Unlike your personal ENCS account, the Group Account cannot be used for interactive logins on an ENCS machine. Instead, you can access the group directory once you log in with your usual ENCS username and password (assuming, of course, that you are a member of the group!). To find out who is in a group, you can use this command in a Unix/Linux shell:

getent group group_name

Only the group's members have permission to create, modify, and delete files in their group directory.

Most Group Accounts have a disk quota of 1GB.

It is important to understand that the ability to write into this shared disk space depends on 'group disk quotas' and not on 'individual user disk quotas'. In other words, it is the group ownership, not the personal ownership, of the files and subdirectories in this group directory that allows the files to reside in the 'group space'.

Some file copy mechanisms, in particular those which try to preserve group ownership, such as 'mv' and some forms of 'tar' in Unix, and such as drag-and-drop in Windows, will not work properly when copying files into a group directory, therefore it is important to verify a file's 'group ownership' if you have trouble moving it into a group dirctory.

For the same reason, it is important that the 'setgid' bit be ON for any subdirectories in that space, otherwise creation of new files in those subdirectories will fail, because those new files would have the wrong group ownership.

E-mail alias which delivers messages to all group members

For most groups, an e-mail alias (in the form 'group_name@encs.concordia.ca') is created along with the Group Account. Any e-mail sent to this alias will be re-distributed to all group members.

Group web page

For non-administrative groups, a group web directory is also created for your group work. The material you place in your group web directory will appear at the URL:

http://users.encs.concordia.ca/~group_name

FAQ

The detailed information with examples can be found in the related Document below.

If you are working with group directories (for example a course webpage), and you encounter an error similar to one of the following while trying to copy in a file:

  • SSH Secure File Transfer - "Encountered 1 errors during transfer"
  • UNIX prompt: "Cannot open file for writing: Disk quota exceeded"
  • Windows drag and drop: "...there is not enough disk space"

Then you will need to set the group sticky bit on the parent directory by typing in the following command at the Unix prompt:

chmod g+s parent_directory_name

... or, under Windows, right click on the directory, click on Properties, and select the Secure Share tab. Make sure that the SGID box is checked 'On'.

Detailed instructions to set up a CVS/SVN repository are given in the document linked below.