Storage and quotas

Disk Quotas

The following storage locations are available on Unix machines:

/home/ login with home directory - it is backed up, located on the home.fi.muni.cz machine, and exported to other machines using NFS and SMB protocols,
/data/ login with more space - it is not backed up, is slower than the home directory, is located there and is exported the same way,
/var/spool/mail with mail - it's backed up, Aisa and Anxur have it separate, on Anxur it's without disk quota
/tmp a /var/tmp with temporary data - not backed up, separate storage on Aisa, Anxur, Aura and Linux stations.

See also remote mounting of these repositories, Windows storage, or the blogpost on disk storage solutions home.fi.muni.cz.

Disk Quotas

A quota limits the space taken up on the storage as well as the number of files stored. A limit always consists of a soft quota, a hard quota and a time limit. When the soft quota is exceeded, the user is set a time limit (grace period) until which he can work normally. After the time limit expires, it is not possible to create new files on the storage or increase the size of existing files - you must delete enough data and/or files to get below the soft quota. The hard limit cannot be exceeded at all.

Determining quota status

For an overview of the limits set, see Faculty Administration. For current quota usage, see the command quota:

aisa$ quota
Disk quotas for user login (uid 55555):
Filesystem       space   quota   limit  grace  files  quota  limit  grace
/var/spool/mail  12K     147M    176M   0      2      50     100    0
/var/tmp         0K      1954M   3907M  0      0      50000  80000  0
/tmp             4K      1954M   3907M  0      2      50000  80000  0
/home/login      47408K  3907M   4883M  0      5841   160k   200k   0
/data/login      4K      97657M  144G   0      2      600k   700k   0

nymfeXY$ quota
Disk quotas for user login (uid 55555):
Filesystem       space   quota   limit  grace  files  quota  limit  grace
/home/login      4882M*  3907M   4883M  6d     5841   160k   200k   0
/data/login      4K      97657M  144G   0      2      600k   700k   0

The first four numeric columns inform about the current usage, soft quota, hard quota and deferral for the occupied place. The next four columns are the same for the number of files. The row you will be most interested in is the one with /home/login.

In the second example, you can see the quota exceeded: the exceeded number is followed by an asterisk and the grace column shows the deferral.

When the quota is exceeded

We automatically inform you once a day by email when a soft quota is exceeded and also when you log in to the text or graphical machine interface. When the quota on aisa:/var/spool/mail is exceeded, the mailbox is eventually moved to the home directory and the user is also notified by a message.

If the home directory quota is exceeded, the graphical login may mysteriously fail. However, if you do not encounter a hard quota for the home directory and you have not expired grace period, you will receive a warning about the quota problem and also be notified by email. Login via the text interface ( Ctrl+Alt+F n) or SSH should always work for you.

What takes up the most space

The ten folders/files taking up the most space in your home directory can be listed as follows:

$ du -hax ~ | sort -hr | head -n 10
7.7G    /home/login
2.4G    /home/login/mail
627M    /home/login/.ccache
414M    /home/login/prog
367M    /home/login/.cpanm
367M    /home/login/.cpanm/work
350M    /home/login/.Spotlight-V100
350M    /home/login/.Spotlight-V100/Store-V1
340M    /home/login/mail/misclass
323M    /home/login/.cpanm/work/1329993381.18167

You can also use the interactive tool ncdu:

$ ncdu -x ~

How to free up space

You can delete some unnecessary files, compress them, or move them to the (non-backup) storage data with a larger quota. For example, delete the contents of the recycle bin:

$ rm -rf ~/.local/share/Trash/files

Too large ~/.vscode-server or ~/.cache/JetBrains can, it seems, be solved by moving to data and a symbolic link. For example:

$ cd
$ # check that no process related to the software is running (where
$ # applicable – most likely on Aisa) and if so, kill them
$ ps ux
$ mv .vscode-server /data/$USER/
$ ln -s /data/$USER/.vscode-server .

A large ~/Library/Developer/CoreSimulator directory should be handled according to the How to use XCode and iOS Simulator tutorial.

If du/ncdu reports significantly less space used than quota, you may have your files in a foreign directory within the repository, or it may also be deleted files still open by running processes on a faculty machine (see ps ux).

If you are still not sure, contact us.