Policies & Queues

Storage Allocations

In general, we give user storage of 5GB on his/her home. This rule applies strictly to the Pollux system, but it is more flexible on the Castor. For a lustre, we determine a quota from a potential proposal separately, case by case. A research group with many people may have a shared directory in the lustre, but not on the home. Shared directory means shared karma if your group’s members are occupying most of the space, please kindly ask them to free it up for you.

A quota on your home

You can check your storage usage on your home by running the command quota -s. An example of the result is showing below.

The group of numbers with units on the left side shows the storage space or block sizes while on the right show number of files or inodes. Mainly, we enforce quota in these two ways. When either block sizes or amount of inodes has exceeded the limit, you cannot add more files to your home directory. Consequently, you need to free up some space by such as moving data to another directory, download or upload it to some container and then remove the existing one on your home. Please be advised that the command rm is quite harsh. Once you remove a file with this command, you cannot recover it in any way.

Looking at the first four columns: quota, limit, space and grace shows how much your data currently occupies on a home. The “quota” and the “limit” are a block-size soft limit and a hard limit, respectively. Your data cannot take up an amount beyond any hard limit (block size or inode). However, when your data is taking up space more than the soft limit but lower than the hard limit, a grace period is enabled. The grace period is a warning, and it is precisely 7 days. It tells you how long you can remain to exceed the soft limit. During this time, if you remove files and then space become lower than the soft limit, the grace period is removed. Otherwise, after 7 days, the soft limit turns into a hard limit, and this is the time to free up some files.

The same principle goes for the inodes (four columns on the right), but in this case, it is a total number of files on that directory.

A Quota on your lustre

We determine a quota on lustre by a project ID on the Pollux, and group ID or group name on the Castor. For a user on the Pollux, we set the project ID to be same as the group ID. Each project quota ties down to one specific directory. You may use the command id to check your group ID. Besides, one user may have multiple groups and multiple projects. Thus, please use the following command to check your use on lustre.

and if you have another project, you may use

On the Castor, where the lustre version is older than on the Pollux, we cannot apply project quota to it. Further, the quota is counted from files’ ownership of the group regardless of their location on this lustre. To check your usage, please use the same command but replace -p <project_id> with -g <group_id>, and you don’t need to choose any directory except /lustre for example

Additional Information

For some user who has little to no idea how ownership is working, please run the command ls -l on a group or a shared directory.

From this example output, at the third and fourth columns, they are user-ownership and group-ownership, respectively. The columns where lustre quota is counting is the fourth columns. You can change the ownership of your files by using the command chown.