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Disk Quota

Disk quota defines the maximum amount of hard disk space allowed for a user's files in his home directory. The user is given 200 MB quota space on SKEW4 when the account is created.

Check Quota and Usage

You can use "quota -v" command to check the quota allocated and usage of space in your home directory.

skew4:quota -v
Disk quotas for xxx123 (uid 1000):

Filesystem       usage  quota  limit    timeleft  files  quota  limit    timeleft
/kellogg/users  75863 200000 250000               1178      0      0

The quota monitoring system reports both the disk space and the number of files created. The first few columns report usage of disk space used while the rest report the number of files in your home directory. For now you can simply ignore the last four columns - all the columns starting and to the left of column "files".

Filesystem: the directory that the quota is monitoring. In the example, it is /kellogg/users, the user's home directory.
usage: the disk space you already used in your home directory. The figure is in kilobytes. In the example, the user has used about 75 MB.
quota: also called "soft limit". It is the maximum space allocated. In the example the user has a quota of 200 MB. A user can exceed his/her soft limit for up to 7 days, up to the space defined by the "hard limit" (see below).
limit: also called "hard limit". The hard limit defines the absolute maximum. In the example, the hard limit is 250MB.
timeleft: grace period left if the soft limit is exceeded. If the usage is under the quota, this column is blank. You have a 7-day grace period to bring the contents of your home directory under the soft quota.

Over The Quota

The first time you exceed your soft limit, you will get a warning message like the one generated in the example below, where a file is being copied:

skew4:cp  temp.dta.gz ~
quota_ufs: Warning: over disk limit (pid 28173, uid 1003, inum 11473467, fs /kellogg/users)

This will prevent many processes like SAS, MATLAB or FORTRAN to run from your home directory though some other activities, like modify, copy and save files are still allowed, but only for a grace period of 7 days. If your disk usage is over your soft limit, then the timeleft column will tell you how much grace time is left.

The hard limit cannot be exceeded at all; you will no longer be able to save/modify/copy any file in your home directory. In some cases, reaching your hard limit can prevent you from logging in.

If you ever hit the hard limit when you try to save some files, please save the file to scratch space first. Make some space in your home direcory as described in the next section. Then copy the file over from scratch.

Getting the quota below its limit

To get your disk usage back below your soft limit, you can do one or more of the following:

  • delete unwanted files using the rm command
  • or move temporary files to /scratch or /scratch2
  • compress any files that you are not currently using, but still want to keep in the server, e.g. use gzip
  • move files that you do not need in the server using sftp to your PC.
  • request an increase in your quota by contacting research computing staff (specify how much space you need)

Be careful only to delete files that you are absolutely sure you do not want, as you may not be able to get them back (see skew backup if you do make a terrible mistake and delete something important).

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