HCC Policies

HCC asks to be notified of any presentation or publication that results in entirely or in part from use of HCC.

Users are asked to include the following line in any publications resulting from the use of HCC within the Acknowledgements section:

Effective January 1, 2017, HCC has established a system of improved scheduling priority for individuals who acknowledge the use of HCC resources in related publications. This will not be a dedicated resource as in priority access, but will improve your position waiting for shared resources with respect to the normal fair share policy. Researchers who acknowledge HCC in publications, proposals, or related work will be entitled to improved priority in the scheduling queue. This priority change will have no affect on current priority access on leased or owned equipment.

Priority increases will be allotted in units of core-years (i.e. the use of one core for a calendar year) according to the following classifications:

Class A: 2 core-years (17,520 core hours)
Awarded for acknowledgements within reviewed publications, dissertations and master theses. Funded grant applications will also receive Class A increases if HCC will be used significantly in the proposed research, or played a role in landing the award (as determined by the PI).

Class B: 1 core-year (8,760 core hours)
Awarded for acknowledgements within undergraduate theses and any reviewed presentations.

Class C: 0.5 core-years (4,380 core hours)
Awarded for acknowledgements in unreviewed presentations, unfunded grant proposals and any published news articles or videos which highlight HCC services.

To submit an acknowledgement, please complete the acknowledgement submission form. If a URL to a digital version of the publication is not available, a PDF version can be emailed to hcc-support@unl.edu upon completion of the form.

If a digital copy is not available, if possible please mail a hard copy of any publications to Hongfeng Yu, SHOR 118K, UNL 68588-0150.

• Users must abide by the Computer Use Policies at UNL.
• One user account is allowed per person.
• To login to any of the HCC clusters, you will need to use SSH. In addition, Duo two-factor authentication is required.
• Users are not allowed to gain access to worker nodes directly via ssh/rsh and work from there, unless special permission has been granted by HCC.
• All jobs that are to be run on the clusters must be submitted via the job schedulers. If you need more information on using them, please take a look at the HCC Documentation.
• You may not run your programs in the background, or run large CPU/memory intensive programs on logon or head nodes. Your jobs will be terminated and your account will be locked.
• Account holders must have an association (student, faculty, or staff) with either an NU campus, Nebraska state college, or other Nebraska-based higher education institution. Exceptions to this requirement for outside collaborators can be made, subject to the following conditions:
  • A non-NU user must be a member of a group headed by a current NU faculty member. An active research or creative activity collaboration between the non-NU user and the NU faculty is required. Proof of collaboration includes, but is not limited to, active grants and/or co-authored papers within 2 years (subjected to annual re-evaluation).
  • Non-NU users need to acknowledge collaborations and HCC resource usage in their publications.
• User accounts created for the purpose of coursework (belonging to a class group) will be removed one week after the course end date. All files remaining in the user's class group directories will be deleted at that time. Users who also belong to a primary research group will also be removed from the class group, and their class group files deleted at this time. Files located in the user's primary (and any supplemental) research groups will not be affected. Full details on how class accounts/groups are treated is available in class-guidelines.docx.

All accounts on HCC machines are to be 'owned' by the research advisor or head of the group you signed up with. This does not allow for a research advisor to snoop through his/her groups' files, but does allow them to retrieve data for research purposes. Further, all files on HCC machines can be searched through by HCC admins for purposes of solving machine problems (ie. checking for breaking of policy or trying to find out why the machine is being bogged down) or for machine security.

By default every user account on an HCC machine belongs to a research group. The leader of this group is often a faculty member directing graduate research, but other arrangements are common. Each group is given access to 3 filesystems, /home, /work, and /common. HCC files for a given user ultimately belong to the research group, although the privacy of each user by default is protected with standard file permissions. No personal identifying data or other data of a private nature should be stored on HCC machines.

Quotas are enforced per individual user on /home. /home is only to be used for files that are necessary for functioning on HCC machines, such as code, difficult to recreate input files, and so on. A best-effort backup is maintained for /home, but this is not an archiving service. The backup is only a protection against catastrophic loss. However, if a user accidentally deletes a file, in a best-case scenario HCC may be able to recover it, and will do so when possible. While exact amounts vary slightly per machine, a quota of 20 GB is common and currently enforced on HCC Clusters. Users may use the command line argument "hcc-du" to check their current storage status.

The /common filesystem is uniformly available on all HCC cluster resources. Quotas on /common are enforced at a group level. Data on /common is not subject to a purge policy, but is also not backed up. It is the researcher's responsibility to back up any valuable data on /common to a more secure location.

The /work direcotry should be used for running jobs, temporary storage of large output files, and so on. The /work fileystem is subject to a per-group quota. If /work fills up, HCC staff will delete existing files as needed to maintain system functionality. Users should never store precious data on /work. Files will be deleted according to age (oldest first) and largest usage amount (per group). All users are asked to remove files from /work as soon as possible. Old files from /work will be removed on a regular basis. Whenever practical, users will be notified before files are removed. Data on /work is not backed up. It is the researcher's responsibility to back up any valuable data on /work to a more secure location.

Researchers who have storage needs beyond the default allotment may purchase storage to be added to HCC machines. For details concerning this, please contact hcc-support@unl.edu.

Contact HCC Support at hcc-support@unl.edu.