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Quotas

How to monitor your quota and what it means

Each user has two types of quotas: personal and project.

Home Directory

For home directories, each user has a personal quota of, by default, 2 GB. This is intentionally rather small as these are backed up with some incremental history.

If you require more space in your home directory, contact cosmos-help@damtp.cam.ac.uk explaining your needs, but please note that storing data files, www browser caches, emails or such is not a valid need.

Monitoring Home File-system Quota

You can monitor your quota with

quota -vs -f /home/cosmos

which outputs something like

Disk quotas for user X (uid Y):
     Filesystem  blocks  quota  limit  grace  files  quota  limit  grace
oberon.private:/nfs/home
                   290M 43807M 43946M          3168   100k   100k

The columns are: blocks simply means how much you have used of your quota. When quota is exceeded, you have first grace column's worth of time to get back under the limit by removing files; after grace has passed, no new files can be created by you on the filesystem. During the grace period, limit is the absolute upper limit which can never be exceeded.

The columns files, quota, limit and the second grace set limits for numbers of files in the same way.

Files on /fast/space

For /fast/space every DiRAC project has a quota set by DiRAC Resource Allocation Committee. You and your project members must agree how to use it and a tidy-up policy etc. DiRAC has no mechanism for requesting more quota, but please contact cosmos-help@damtp.cam.ac.uk if you desperately need more space: we may be able to find a temporary solution anyway.

Additionally, some DiRAC projects have subprojects whose quotas are fractions of the DiRAC project quota and decided by the project internally.

It works exactly like the home quota otherwise.

Monitoring /fast/space and /slow/space quotas

Due to CXFS causing incompatibility with the quota command, /fast/space quotas must be monitored with

xfs_quota -x -c "quota -h -g dpXXX" /fast/space

where dpXXX is your project ID. This will output something like

Disk quotas for Group dpXXX (GID)
Filesystem   Blocks  Quota  Limit Warn/Time    Mounted on
/dev/cxvm/cosmos2-space
                 XT     YT     ZT 00 [------]  /fast/space

Unlike the home filesystems, /fast/space has only block quotas and the grace column is called Warn/Time, but otherwise the quota works in exactly the same way.

Finding your files

When you run out of quota but have no idea where your big files are, you can try to find them using something like the command (you did not use spaces or special characters in your filenames, did you?)

find /fast/space/ -maxdepth 5 -user my_username -type d|sort|xargs du -sh

Please note, however, that this causes a huge amount of file-system transactions, so should not be used regularly.

If the above command does not reveal the files taking up the quota, it most likely means someone else in your project owns them. Unfortunately, there is no guaranteed way of finding the culprit this case, because you may not have access to all the files your project owns. If your collaborators have no prevented you from accessing their directories, you can find the file using the command

find /fast/space/ -maxdepth 5 -group my_groupname -type d|sort|xargs du -sh