The NCCS uses a Standard Billing Unit (SBU) for allocating and tracking computing time usage. The new SBU tracking system started to appear in usage reports October 2018. View the full set of SBU Conversion Factors and an explanation of changes on the NASA High-End Computing Website.
| ARCHITECTURE | Supermicro TwinPro | Supermicro TwinPro | Supermicro FatTwin | SGI Rackable |
| PROCESSOR | AMD Milan EPYC | Cascade Lake | Skylake | Haswell (retired 7/2023) |
| CORES PER MAU | 126 usable | 48 | 40 | 28 |
| SBU2 (CURRENT) CONVERSION FACTOR | 4.08 | 1.77 | 1.61 | 0.81 |
| SBU1 (RETIRED) CONVERSION FACTOR | N/A | N/A | N/A | 3.09 |
The new SBU represents the amount of work that a Minimum Allocatable Unit (MAU) can perform in one hour on a baseline system. Usage on a system that completes more work with 1 MAU in 1 hour will be charged at a higher rate. Systems not as powerful as the baseline would charge at lower rates. For Discover, 1 MAU is one Node.
Charging Formula
SBUs Charged = (# of Nodes) * (# of Wall Clock Hours) * (SBU Conversion Factor)
Given that an SBU is a representation of an amount of useful work, a job should be charged similar amounts of SBU’s whether it is running on a more efficient or less efficient system.
Requesting Allocations & Checking Usage
When using the eBooks online submission system to apply for allocations, principal investigators should continue to estimate the number of runs on each processor type of a system, the number of processors per run, and the wall clock hours per run. Calculators within eBooks total the processor-hours from these estimates and convert the processor-hours to the common SBUs.
The “allocation_check” command on Discover should be used for checking the amounts allocated and used.