Filesystems on NAS systems have the following types of quotas:

• Limits on the total disk space occupied by your files
• Limits on the number of files (represented by inodes) you can store, regardless of size. For quota purposes, directories count as files

Hard and Soft Quota Limits

NAS quotas have hard limits and soft limits. Hard limits should never be exceeded. Soft limits can be exceeded temporarily, for a grace period of 14 days. If your data remains over the soft limit for more than 14 days, the soft limit is enforced as a hard limit. On some filesystems, this means that write attempts will fail. On other filesystems, it will mean that your PBS jobs will no longer start. To reduce your data to below the quota limits, you can delete unneeded files or copy important files elsewhere, such as the Lou mass storage system, and then remove them locally.

Filesystem quotas are shown in the following table:

To learn how to check your disk space, inode usage, and quotas, see the following articles:

• Home Filesystems for NAS Compute Resources
• NAS Lustre Filesystems
• The Lou Mass Storage System

Email Warnings and Consequences

It is expected that your data will exceed your soft limits as needed. When this occurs, you will begin to receive daily emails to inform you of your current disk space and how much of your grace period remains. However, if your data is still over the soft limit or if you reach the hard limit, restrictions are put in place.

Once you exceed your filesystem limits, PBS will return the following error and prevent you from submitting new jobs:

qsub: Filesystem quota exceeded! Please reduce your usage or request an increase before submitting.

The following table shows the quota enforcement policy for each type of filesystem.

More details are available in the following sections.

Lustre Filesystems (/nobackuppX)

If your grace period has expired, then your batch queue access is restricted and no new jobs can be run until your data on the Lustre filesystem is reduced to an amount below the soft limit. Any jobs that are running will continue to run. If you reach the hard limit, your batch access is immediately restricted, but any running jobs will continue.

NAS Compute Systems Home Directory and /nobackupnfs2

If your grace period has expired, then any writes to that filesystem will fail, and any jobs that attempt to write to the filesystem will fail. You will be unable to write to the filesystem until your data is reduced to an amount below the soft limit. Similarly, if you reach the hard limit, any writes will immediately fail and you will be unable to write to the filesystem until your data is reduced to an amount below the hard limit.

Lou Home Directory

If your grace period has expired, then any writes that attempt to create new files will fail. You will be unable to create any new files until the number of files is reduced to below the soft limit. If you reach the hard limit, any writes that attempt to create new files will fail until the number of files is reduced to below the hard limit.

The maximum size of a tar file moved to Lou should not exceed 2 TB. If you need to archive larger files, please contact the NAS Control Room at support@nas.nasa.gov for assistance.

Note: The Shift tool, which is a convenient way to transfer files to Lou, can created a set of smaller independent tar files from a single large directory. For more information, see Shift File Transfer Overview.

Changing Your Quotas

If an account needs larger quota limits, send an email justification to support@nas.nasa.gov. Your request will be reviewed by management for approval.