16.0 About green computing
To conserve energy, Moab can automatically turn power off idle nodes that have no reservations or running workload on them. Conversely, Moab can automatically power on additional nodes when jobs require such. For Moab to automatically perform these power management functions, you must configure Moab for green computing operation.
Using the MAXGREENSTANDBYPOOLSIZE parameter, you can specify a "green pool" size, which is the number of idle nodes Moab keeps turned powered on and ready to run jobs (even if some nodes are idle). Moab turns off idle nodes that exceed the number specified with the MAXGREENSTANDBYPOOLSIZE parameter. Thus, Moab automatically powers nodes on and off using a power provisioning resource manager to keep the green pool of idle nodes at the configured size.
Moab can work with various power management solutions such as IPMI, iLO (HP), DRAC (Dell), xCAT (IBM), and others. Adaptive Computing has provided some IPMI-based reference scripts you can use to deploy a green computing solution. The examples in this section will generally refer to our reference scripts and to IPMI power management. You can modify our supplied scripts to use your own power management system's commands or you can create your own scripts.
If you intentionally power off a node, a green policy might try to turn it back on automatically. If you want the node to remain powered off, you must associate a reservation with the node before you power it off. After you finish with the node, you can return it to service by deleting the reservation.
Tasks associated with green computing:
The following sections include information about the configurations and settings needed to use green computing.