Quota Management

In most cases the filesystem for a group or institute on exported by the iiStore cluster is a shared resource. Disk quotas in two forms can be used to control or limit the usage of the available space per user or group of users:

• A real disk quota which is actually enforced by the file server
• A nagging quota which is enforced by your IT coordinator or isginf

What kind of quota is active for the filesystem(s) where your data is depends on the policy chosen by your group or institute. We generally recommend that a nagging quota is used for medium sized or large groups or institutes. Additionally a large real quota is recommended to prevent users from accidentally filling up the filesystem with a runaway job or the like.

For filesystems containing only student data we recommend to enforce a real quota.

Cleaning Up

When your disk usage is close to or over your disk quota first try to clean up before requesting a larger quota. Things that typically free up a lot of space when deleted are:

• Old software installers or source packages
• Old build directories
• Core files
• Old CD/DVD image files

Data you rarely use (e.g. old projects, test results, etc.) can be archived and compressed using one of the available file archivers:

• infozip (zip -r archive.zip file|directory…)
• tar (tar -jcf archive.tbz file|directory or tar -zcf archive.tgz file|directory)

If you really need to increase your disk quota you can contact your IT Coordinator or isginf.

Real Quota

The real quota is managed by the filesystem on the file server. There are two limits for both the used space in kilobytes and the number of files owned.

Soft Limit

The soft limit can be exceeded for a limited amount of time ("grace time"). Unless otherwise requested the default is 7 days. If the soft limit is exceeded for more than 7 days it becomes impossible to write more data or create new files.

Hard Limit

The hard limit cannot be exceeded. If the hard limit is reached it becomes impossible to write more data or create new files.

Nagging Quota

The nagging quota is not enforced technically. The name comes from the effect the mail notifications have that are sent every day as long as the disk quota is exceeded in some way.

There are two limits for both the used space in kilobytes and the number of files owned. The first or soft limit will just trigger a notification mail to you when exceeded. If one of the second or hard limits is exceeded a copy of the mail will also go to your IT coordinator and isginf.

You can check the user account settings for nagging quota here.

Notification

A mail notification is sent when a real or nagging quota (either number of kilobytes or number of files) is exceeded. These mails are sent every day until your usage goes below the given limits. If the hard limit is reached or exceeded a copy of the mail will also go to your IT coordinator (and isginf).

How to Check Volume Size, Real Quota and Usage

Instructions on how to find out the available space and disk quota for your home directory can be found in the sections below. The same methods of course also apply to project shares and other data shares.

Linux

On a linux system you can issue the command df -h ~ to find out more about the available disk space on the volume where your home directory is:

> df -h ~
Filesystem            Size  Used Avail Use% Mounted on
fs.test.inf.ethz.ch:/export/groups/test/h1/home/walteste
                      100G   51G   49G  51% /home/walteste

To query your real quota and disk space usage you can use the command quota -v:

> quota -v
Disk quotas for user walteste (uid 50515):
     Filesystem  blocks   quota   limit   grace   files   quota   limit   grace
fs.test.inf.ethz.ch:/export/groups/test/h1/home/walteste
                   28308   60000   80000             370     500    2000

Block sizes are in kilobytes.

Windows (XP/Vista)

On Windows XP or Vista you can view the properties of a network drive mapped to your home directory:

The meaning of the values depends on whether there is a real quota active or not:

Furthermore, if a real quota is active and the limit for the number of files is exceeded, the free space will drop to 0 regardless of the block usage.

MacOS X

Under MacOS X you can view the quota using Get Info in a Finder window displaying you home directory (or any subdirectory in there):

The meaning of the values depends on whether there is a real quota active or not:

Furthermore, if a real quota is active and the limit for the number of files is exceeded, the free space will drop to 0 regardless of the block usage.