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Computing  Understanding Your Quota

What are Quotas?

There are two Departmentally owned and operated servers which store data on behalf of users: "Willis", the file server, and "Wren", the mail server.

With a large user community to serve and a finite amount of disk space available on each server we need to apply restrictions to ensure a reasonably fair sharing of resources and discourage wasteful use. Both servers therefore operate a series of restrictions called "quotas". On each server each user has two limitations applied to them, known as the "soft quota" and the "hard quota".

The hard quota is the amount of disk usage that the user may not exceed at any time.

The soft quota is a lower limit, which the user is allowed to breach for up to a week.

The difference between the hard and the soft quotas effectively forms a disk space "overdraft" facility - allowing the use of the file server as a way point in moving large collections of data around the network or gathering files together for writing to the Department's CD Writer, for example.

The default soft quota given to new users on both servers is 100Mbytes. This value is deliberately set low, to encourage users to be economical and efficient in their use of the file server. This limit is intended to be negotiable - if users have legitimate requirements for more storage they are welcome to ask for an increased quota. Email your request to computing@physiol.ox.ac.uk.

The default hard quota applied to most users on both servers is 750Mbytes. This limit may occasionally be temporarily relaxed in special circumstances. You should note, however, that as a matter of Departmental policy we do not provide gigabytes of mass storage to individuals (such provision is the responsibility of research groups).

Where is the Disk Space Being Used?

It is important to understand that the two servers count usage, and have quotas set, entirely independently - your mail folders don't count against your file quota, and files that you store in your home directory don't count against your mail quota (assuming your mail program is correctly set up!).

Most files belonging to you on the file server are likely to be in your "home directory" - a personal storage area for your files and for the configuration information which makes the various networked programs run. Different network clients see this area in different manners:

• Under Unix you will see a directory /home/willis/username.
• Logged in to a PC you will see a network drive P:.
• Logged in to Macintosh you see a volume Home Directory.

In addition to the home directory there are other areas of the file server where you might own files, including shared file areas, such as the "S: drive".

Your current usage of the file server is calculated by adding up all space used by any file belonging to you in all of these possible locations. This is the figure which is compared against your quotas.

If You Go Over Quota

At the point when your usage of the file server exceeds your soft quota a seven day timer starts running. If you go back below your soft quota at any point the timer gets turned off and reset. If you were to stay above your soft quota for the full seven days and allow the timer to expire the system would clamp down and prevent you from using any further disk space. This restriction would stay in force until you removed enough files to bring your usage below the soft quota again.

You should make efforts to avoid this "expired" state - many programs don't work properly when write access is denied to your home directory. Some PC software notably fails to cope with the situation where it is allowed to open a file for writing, but the actual write operation itself is denied. This results in corruption of configuration files for programs like ECSmail and Netscape.

Checking Your Quota

You can use a web browser to check your current usage and quotas at any time by visiting the "Check your quota" page in the "Account" section of the Computing web, or by accessing the URL

https://www.physiol.ox.ac.uk/Computing/Account/Check_Quotas.cgi

directly and logging in with your network username and password.

You can also check your quota by making an SSH connection to "m5.physiol.ox.ac.uk". Log in with your normal Departmental username and password and type the command "quota -v" This should produce output similar to this:

Filesystem     usage  quota  limit    timeleft  files  quota  limit    timeleft
/home/willis   64307 102400 768000              10486      0      0            
/home/mail     60999 102400 768000                845      0      0            

The "/home/willis" line tells you about your file server usage, the "/home/mail" line tells you about your mail server usage. The usage, quota and limit figures are expressed in kilobytes. The usage figure tells you how much space you are currently using. The figure in the "quota" column is your soft quota, and the figure in the "limit" column is your "hard quota", as discussed above.

If you are currently over your soft limit you will see a message of the form:

Filesystem     usage  quota  limit    timeleft  files  quota  limit    timeleft
/home/willis  120537 102400 768000    6.0 days    148      0      0            

The "timeleft" column tells you how long your disk space "overdraft" has to run. If the timeleft field contains the string EXPIRED then you are already out of time.

The columns beyond the first "timeleft" column can be ignored - the quota system can be used to regulate the number of files created by users, in addition to the amount of space those files consume. We don't use this feature.