Storage

We have 3 storage systems for you: $HOME (/home/<NetID>), $SCRATCH (/scratch/<NetID>) and $ARCHIVE (/archive/<NetID>).

Note

Kindly note that $WORK is now discontinued. $WORK and $ARCHIVE are mereged together to $ARCHIVE to incoporate both their functionalities into one. Kindly refer the doc here for the major changes

In short, you should

• Put all your data to $SCRATCH and run your jobs from there.

• Only a small persistent fraction to $HOME (e.g., source code, executables).

• For long-term storage, archive them to $ARCHIVE.

• $ARCHIVE is not visible on compute nodes but mountable on your local workstation, best suited to quick post-processing, analysis and visualization, without moving your data.

Important

Backing up is a user’s own responsibility. E.g., if a user deleted something accidentally, we can not recover, unfortunately.

Caution

Running jobs from /home is a serious violation of HPC policy. Any users who intentionally violate this policy will get their account suspended. $HOME SSDs are not designed for this purpose, it will kill the SSDs quickly.

• $HOME and $SCRATCH
• $ARCHIVE
  • What’s inside $ARCHIVE
  • State of the file in $ARCHIVE
  • How to identify the state of a file
  • How to Archive and De Archive
  • Quick Glance into the archive commands
  • Summary
  • Best Practices
• Data Sharing with Collaborators
• Data Sharing with ACL
  • Introduction
  • Access Control Lists (ACL) Levels
  • Viewing Permissions
  • Setting Permissions
  • Removing Permissions
  • Flags
  • Additional Information
• Data Sharing Risks
  • What Does chmod 777 Mean?
  • Command Explanation
  • Numeric (Octal) Representation of Permissions
  • Risks of Using chmod 777
  • Safer Alternatives
  • Best Practices
• Merge of $WORK and $ARCHIVE
  • Summary
• Mount $ARCHIVE with SSHFS
  • Step-by-step guide
  • Mount $ARCHIVE on Windows

Summary

	$HOME	$SCRATCH	$ARCHIVE
Use for storing	source code / executables	data	anything
Accessible From	login / compute	login / compute	login
Use to Run Jobs	No	Yes	No
Retention Time (Days)	No Limit	90	No Limit
Mountable	No	No	Yes
Default Quota	50GB, 500K Files	5TB, 500K Files	No Limit

Know Your Quota

• Run myquota command in the terminal on the HPC to check your current usage and quota where it is only accessible from the login nodes. Example output:

                DISK SPACE                # FILES (1000's)
filesystem       size      quota            number      quota
            --------------------------   --------------------------
     /home       92KB       50GB (  0%)         0       500 (  0%)
  /scratch        4KB     5000GB (  0%)         0       500 (  0%)
  /archive        4KB     5120GB (  0%)         0       125 (  0%)

For data transfers please refer to the Data Trasnfers section here

Best Practices

Dos	Remarks
Periodically clean your /scratch	Files which have not been accessed for 90 days in /scratch are deleted.
Once a project is completed move the data over to /archive using this link	Moving data to /archive frees up space from /scratch and avoids deletion of files if older than 90 days.
Use tar files to archive directories with large file count	Lesser the number of files, faster is the archiving and dearchiving process