HPC Allocation Service: FAQs

The Intersect / UniSA HPC as a Service (HPCaaS) will be a little different from the Tango service that you may be used to. This article and FAQs will help to explain how the HPC Allocation Service works.


To run jobs on Gadi, you need an allocation of Service Units. How many service units you will need per job will depend on many things: the number of CPUs, the amount of memory, and the urgency of your job. Some jobs will cost 2 SUs/hour, others up to 6 SUs/hour. The NCI allocate SUs to projects – not individual people.

Through Intersect, UniSA has purchased a ‘bucket’ of Service Units that will be allocated amongst HPC users’ projects. You will need to know how many SUs you will need in order to request an allocation. You can find out how to calculate the number of SUs needed here.

Allocations are made on a quarterly basis (January – March; April – June; July – September and October – December). Any unused SUs are forfeited as they cannot be carried over from one quarter to the next. To help maximise usage and minimise waste, Intersect’s eResearch Analyst for UniSA will conduct a mid-quarter review every quarter to determine if any SUs can be re-allocated between other UniSA HPC projects. If you have SUs to spare, please return them the the ‘bucket’ so they can be re-distributed to those who can make use of them. 


Q: I have 5 people in my research group. Do I need to request an SU allocation for each of them?

A: No. When you register with NCI, you will be asked to create a project. You will then need to estimate how many jobs you and your research group will do each quarter, and how many SUs each job will cost. You then request that number of SUs, and if approved by the UniSA Steering Committee, they will be credited to your project.

Q:  If I use all of my SU allocation in the first 2 weeks of the quarter, can I request more?

A:  You can request an increase in your allocation and if at the mid-quarter review there are unused SUs, it may be possible for some to be re-allocated to your project. This is not guaranteed, and if you do receive re-allocated SUs in one quarter, it does not mean that you will receive the same next quarter.

Q: I underestimated how many SUs I need each quarter. Can I request a different amount for the next quarter?

A: Yes. You can request an increase in your allocationand if approved by the UniSA Steering Committee, they will be credited to your project.

Q: Is there any additional cost to me or my research group to use the Gadi HPC?

A: No. UniSA has entered into an agreement with Intersect to provide access to HPC at no cost to individual researchers.

Last updated: 10 May 2022

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