IMSc HPC systems have evolved over time keeping in mind the usage requirement of the users at IMSc. It is a heterogeneous computing environment catering to different hardware and software requirements of IMSc users. A brief overview of the present computing facilities and information regarding various compilers, libraries and software installed on the systems can be found at https://hpc.imsc.res.in/clusters

In the following sections, we explain the usage policy for IMSc HPC systems. Any signed user form will be automatically deemed that the usage policy has been carefully read and understood and it is the user’s responsibility to comply with the policy rules as long as they want to use the IMSc HPC facilities. Ignorance of the policy rules will not be considered as a justification for a possible violation of the same at any point of time.

ACCOUNT GENERATION AND VALIDITY

1. A HPC user account is required to access the IMSc HPC facilities. A valid IMSc mail account is required but does not automatically extend to having an account on HPC systems. To get an cluster account, send an email to CC chairman (cchair AT imsc DOT res DOT in).
2. Several user categories exist on the IMSC HPC systems.A brief description is given below:
   
   • Faculty: Any IMSc faculty member can have an account on IMSc HPC systems after filling the account form.
   • Student/PDFs: Any student registered in IMSc and Postdocs joining IMSc can have an account on IMSc HPC systems, after filling the account form, duly signed by a faculty advisor.
   • Project students: Any student joining a faculty member as a project student can have access to the HPC systems at IMSc after filling the account form duly signed by a faculty advisor. The faculty advisor should clearly mention the duration of the project.
   • Visitors: A visitor or collaborator of a faculty member at the institute can be granted limited access to HPC systems only after aclear justification and duration of the account (to be renewed every year and limited to 3 years) is given by the faculty member to the computer committee for approval.
   • Outside users: Any member belonging to another academic institute can seek to have a very limited access to IMSc HPC system ( not exceeding 16 cores) by submitting an project proposal application to the computer committee, provided this does not hamper the computing needs of the IMSc users. Submission of an application is not aguarantee of provision of computing account. The application should clearly state the research objective, justification for required computing usage and duration of usage. The user should comply with access restrictions to HPC systems from outside and work with system administrators to ensure security of the systems. The user is also required to include the HPC systems at IMSc in the acknowledgement, ifthe work done on IMSc HPC systems results in a publication.
3. HPC Computing account of any user who leaves the institute will be disabled automatically. The data, however, will be stored for a mandatory period of 24 months, unless special permission is sought. Prior association of a user to IMSc does not guarantee continued privileges of that category after the user leaves IMSc. For example, a registered student of IMSc who leaves the institute but still wishes to use IMSc computing facilities will be relegated to other categories of either project/visitor etc., and the rules governing these categories will be automatically applied.
4. A user account at IMSc HPC system should be used only for academic purposes and cannot be used for any monetary benefit of individuals or for any corporate work. If your work falls under these categories, please send a specific email to the compute committee stating the purpose, conflict of interests and justifications for such usage.
5. Any form of publication resulting from work done on HPC machines at IMSc should include a citation similar to the following:

The simulations and/or computations required for this work were supported by the Institute of Mathematical Science’s High Performance Computing (hpc.imsc.res.in) [clusternames]

An e-copy of the published paper, book chapters, conference proceedings etc., should be sent to the system administrators, to enable the inclusion of the same in IMSc HPC/CC yearly work report.

SECURITY AND RESOURCE ABUSE:

1. IMSc will never send you unsolicited emails requesting confidential information or passwords. Please be wary of such emails and contact system administrators immediately. They are just one phone call away during working hours (extensions: 221, 222, 217) and via email(service@imsc.res.in, gsmoni@imsc.res.in, ravi@imsc.res.in, mangal@imsc.res.in)
2. Users must connect to all the computing facilities via ssh and the computer systems at IMSc are monitored for any security violations.
3. The IMSc HPC resources are vital to our scientific community and hence it is our responsibility that the facilities are used in a responsible manner so as to enable fair usage by all the users. Resource abuse includes, but not just limited to:
   
   • Sharing passwords with other users. The system administrators have the right to verify this from time to time and for any user. If found in violation of this rule, the UserId will be canceled after one warning to the user. The account will be reinstated only after justification report is sent to and approved by the computer committee.
   • bypassing agreed norms among the users and taking over large swaths of CPUs, without any prior intimation to system administrators or other users
   • doing memory-intensive analysis or visualisation on head nodes, thereby slowing down the computing of others
   • generating data in excess to agreed user quotas and/or leaving enormous data untouched for years
   • using IMSC HPC system disks as backup storage for personal desktop data etc.,
4. Given the heterogeneous nature of the computing facilities and with the aim of optimal usage of our computing resources, the following guidelines will be followed:

single node, serial jobs are heavily discouraged on computer clusters involving inter-node network like Infiniband.

RUNNING JOBS in HPC systems

In view of better utilization of the cluster by all users, the HPC committee has decided on the following rules.

1. For running any job on Annapurna or the parallel queues in Nandadevi, the the job has to utilize at least two nodes, i.e. 16 cores on Annapurna and 32 cores on Nandadevi. Jobs using lesser number of cores will not be allowed.
2. Maximum run time for any job on the clusters will not exceed 2 days(ie. 48 hrs). The job will be automatically killed if the run time is exceeded. So, please have checkpoints in your code to ensure that job finishes within the stipulated run time and that you have the necessary restart files to re-run the jobs. If you need any help regarding this, please contact the system administrators.
3. At any given time, any user will be allowed to use 50% of the total cores available in the cluster.
4. Maximum number of job can be queued in "Q"/waiting state is 5 and if the users current usage is 50% of total available cores then no more job are allowed to queue till the job finishes.

If there are any special requests, it is the user's responsibility to intimate all the users (at-least > 24 hrs) and make special arrangements for running of their jobs. This should include a clear statement of why extra cores/longer times are needed, not just a note declaring such a need.

LIMITS on NANDADEVI

GETTING STARTED AND HELP

Frequently asked questions regarding the HPC accounts at IMSc such as “How to log into HPC machines?”, “What is the CPU time limit a job is allowed to rub?”, “Is there an example scheduler submission script available?”, “What is the disk quota I am allowed?”, please look at the FAQ page

If you have any additional questions or concerns, please send an email to hpc@imsc.res.in