Storing data

Windows

In Windows, H:\ is mapped to your home directory on the file server which is reliable and does backups. The Desktop is mapped onto H:\Documents, but many other Windows app directories are copied back and forth from/to the file server when you login/out.

Linux

Under our Linux systems there are four ways to save data. Some of them are only intended for temporary storage and should not be used for data which is critical.

$HOME (same as ~/)

This is your home directory. It is the only place to store data which you wish to keep. Your home directory is saved by the backup system every night, but you have a limited amount which can be saved here.

(To see how much you have saved and how much you are allowed to save, use the quota command. For more information, see below.)

/import/bulkhome/$USER

This is another network filespace, similar to your home directory, but with more storage quota available (default 50GB) intended for storage of large files and caches (ie. bulk data).

It has less redundancies & backup than the regular home directory, so it's not intended to store important files (such as source code you've written), but rather as a place to store bulk-data such as ISO-files, disk images, downloaded files, and caches.

Basically, if it's data that you can download or reproduce it can be stored in bulkhome, but if it's data that you've produced yourself that cannot be recreated it should be stored in the regular ~/ home directory.

/scratch

Scratch uses the data area which remains on the hard disk of the local machine after after all other necessary items are installed on the disk.

The scratch area is not backed up, and its contents will be erased automatically when it begins to become full.

When to use: When you need high performance storage for temporary files, ex. if you are analyzing large datasets storing the files over network may be prohibitively slow due to its very low random seek performance, so copying the files over to /scratch will likely be a huge boost. Make sure to only use it as a temporary storage however, and copy any important files/results/.. back to your home- or bulkhome-directory afterwards.

/tmp and /var/tmp

These are the wrong places to save large quantities of temporary data. This space is used by applications to save temporary data; if it becomes full these applications will function poorly or not at all. Therefore, do not use this area for other purposes than quick storage of smaller amounts of temporary data. This directory is emptied with each boot of the machine and older files are purged automatically while the system is running.

Accessing your data from remote

You can access your files when away from the department, see https://webapps.cs.umu.se/files/.

Space in your home directory

The space which a student is allocated in the home directory is based upon the number of courses which that student is currently enrolled in.

At this moment, the following limits apply.

• A base quota of 1.1GB (1100MB)
• Additional 250MB quota per course
• Maximum quota is 8GB (8000MB)

For example:

• A new student which hasn't registered on any course gets 1100MB quota.
• A student who is on his/her 2nd year and has taken approx. 8 courses gets 1100MB + 8*250MB = 3100MB.
• A student who has taken 30 courses will get 1100MB + 30*250MB = 8600MB, but as the maximum quota is 8GB the student will have 8000MB quota.

For employees: Quotas are mainly used as a practical measure to protected against runaway programs which would otherwise fill the disk with garbage.
If you run out of space, speak with a system administrator to solve the problem.