Computational Cluster Programs

Data Storage on the Hoffman2 Cluster

Your Home Directory

All user home directories are physically located on the BlueArc Storage Server.

Users of the Campus General Purpose Cluster:

Each user of the Campus General Purpose Cluster has a home directory which is accessable from the head node and from each of the compute nodes. The home directory is named:

/u/home/campus/loginid

You can get to you home directory by entering the command:

cd

without any arguments.

Users of the Campus General Purpose Cluster have a 5 GB disk space quota on their home directories. Use the:

quota

command to determine how much of your quota is remaining.

Participants in the Shared Cluster Hosting System:

Research groups participating in the Shared Cluster Hosting System, purchase disk space in units of 1 terabyte, and are subject to group quotas on the BlueArc Storage Server. Use the:

quota -g

command to determine how much of your groups quota is remaining. A group's quota will grow whenever the group purchases additional disk storage. Individual quotas are not used unless directed so by the research group's PI.

If you belong to a research group that participates in the Shared Cluster Hosting System, your home directory is named:

/u/home/research_group_name/loginid

All home directories are incrementally backed up nightly. In case of catastrophic failure on the BlueArc, all data in home directories will be restored to the way they were when the last backup was taken.

The purpose of the backup is not to be able to restore individual files that you accidentally loose. There are measures that you can take to protect your files from accidental loss.

File Systems for Temporary Use

/work

Each head node and compute node has a local scratch file system named /work which at minimum is 100 GB. There is a different /work on each node.

• To place files in /work, make a directory there named with your login id and place the files in it.
• In particular, it's good to use the /work file systems for scratch files (life of the program), and high activity files to avoid the overhead and network traffic associated with the network file systems.
• Once a day, files in /work that have not be used in the last 24 hours are deleted.

/u/scratch

• This file system is available on all nodes of the Hoffman2 cluster.
• Because /u/scatch resides on the faster fiber channel attached disks, it is recommended that for performance reasons, parallel jobs, especially those with high I/O requirements, write to /u/scratch instead of to the home directories.
• To place files in /u/scratch, make a directory there named with your login id and place the files in it.
• The amount of space in /u/scratch is in the terabytes. Enter the command:

  df -h /u/scratch

  to see the current size.
• Under normal circumstances, files you store in /u/scratch are allowed to remain there for 7 days. Any files older than 7 days can automatically be deleted by the system to guarantee that enough space exists for the creation of new files. However, there may be occasions when even though all files older than 7 days have been deleted, there is still insufficient free space remaining. Under that circumstance and that circumstance only, some of the files belonging to those users who are using the preponderance of the disk space in /u/scratch will be deleted even though they have not been there for 7 days.