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Home Space

Each user account is given a home space for personal file storage located at /mnt/home/$USER, where $USER is the environment variable of the user's login name. Alternatively, it can be accessed at ~/, though this shorthand may not work in some scripts. By default, it is only accessible to the user. It is often referred to as the “home directory” since this is the beginning directory after login of any HPCC node.

Every home space starts with a 50 GB limit for file storage space and can not contain more than 1 million files. To check the quota and used space of your home directory, see the Space quota section. You can request to increase your quota up to 1TB by completing Quota Increase Request form. Storage space greater than 1TB is available for an annual fee paid through a MSU financial account. Users can find the fee and submit their request by completing the Large Quota Increase Request form. If you would like to store more than 1 million files in your home space, please refer to the section Limit on number of files.

All home directories are stored in the IBM General Parallel File System (GPFS). It is automatically backed up except files saved in the nodr space. To restore any file from backup, please submit a ticket and let us know the paths to the files or the directory with the time frame you would like them restored.

For the system security and user data privacy, we recommend that users do NOT open home directory access permission to others. When you report an issue about files saved in home, please attach them to your message for reference. ICER staff cannot access any files or directories in your home directory.

Warning

Currently our home file system check quota function will sometimes cause a user's directory over the quota due to incorrect calculation of used space.  If you see this please open a ticket and we will work with you to temporarily increase your quota.  We continue to work with our vendor to correct this issue.

Space quota

The only way to get quota information of home space is to run the command quota:

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$ quota
home directory: Space    Space   Space     Space     Files     Files     Files     Files        
                 Quota    Used    Available % Used    Quota     Used      Available % Used
-----------------------------------------------------------------------------------------------
/mnt/home/$USER  50G      32G     18G       64%       1048576   432525    616051    59%

where all file spaces accessible to the user are listed, including home, research, and scratch. In each space, the information of quota, usage and availability on space size and number of files can be found. If "Free" or "Available" is a negative value (such as the "Space Available" column in the above example), the usage is over the quota, please remove, transfer or compress some files so the used space or the file count can be lower than the "Quota" value.

Actual disk usage (du) different from quota results

The GPFS system set the smallest file block size to 64KiB. This means that files between 2KiB and 64KiB will occupy 64KiB of space. This causes space usage to be greatly inflated for users with large amounts of small files. One suggested solution would be to compress many small files into one large file (larger than 64KiB). In this way, the number of files can also be reduced. If you still have any difficulty, a temporarily larger quota can be requested if your quota is at 1TB with many small files.

Limit on number of files

Besides the quota on the size of space, users are also limited to 1 million files in their home or research directory. We need to set this limit because, with a great number of files, the file system will spend too much time on backups to be able to function normally. If possible, users can compress many files into one to reduce the file number.

If users do not wish to have the limit, they can request to have a portion of their home quota (or research space) moved under nodr space (/mnt/ufs18/nodr/ or /mnt/ufs18/nodr/research/) by submitting a help ticket with the drop-down subject 'other' and secondary subject 'nodr request'. There is no limit on the file count, but there is no backup of these files either. Users will be responsible for their own backup of files in the nodr space.

By default, one half of the current home quota is assigned to the requested nodr space. The original quota under /mnt/home/ (or /mnt/research/) is then reduced to half the original quota so the total space quota remains the same. A different size of nodr space can also be assigned based on the user's request. Once this space is created, the path and the quota information on both home and nodr space can be found using quota command mentioned above.

Backups

All home space files are periodically, automatically backed up (except those files that a user has opted to store in a specially requested nodr space). To access file backups, please submit a help ticket containing the file paths and the period, i.e. the time frame, from which the files should be restored.