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Emergency Power Reduction
21 Benchmark the Performance, Reliability and Scalability of Dell EMC OpenManage Enterprise Power Manager
2.0 in Data Center Environment
8 Emergency Power Reduction
Emergency Power Reduction (EPR) is a feature in Power Manager which helps you to reduce power
consumption of devices immediately during a power emergency. Apply EPR on Individual Devices using the
Apply EPR option that is available in Power Management and Monitoring > Policies and EPR tab. And,
apply EPR on Static and Physical Groups using the Apply EPR option that is available in Group Details >
Policies and EPR tab. Throttle and Shut Down are two modes of applying EPR on target devices and
groups.
EPR Throttle: On applying EPR (Throttle), all the selected devices consume extremely low power and hence
impacts the performance of the target device.
EPR Shut Down: On applying EPR (Shut Down), all the selected devices monitored as Individual device or
as part of the groups are gracefully shut down.
8.1 Configuration Details and Generic Recommendations
8.1.1 Configuration Details
Applying the EPR is supported on individual devices, static groups and physical groups. Test for individual
devices has been performed by applying 400 EPR’s (sequentially) for 400 servers in Power Manager, from
REST interface with a delay of 5 seconds set between subsequent EPR actions. In case of groups, the
devices were distributed across 5 Static and Physical Groups (40 servers each) and the EPR was applied
sequentially when the preceding task was completed. Data is collected for the EPR Throttle and EPR Shut
Down actions from Power Manager.
8.1.2 Recommendations
After analyzing the impact and test results, following are the recommendations for using the EPR feature:
• EPR Throttle action throttles down the device power down to an extremely low level, which impacts
the performance of target device. Hence the recommendation is to use this feature only in case of an
emergency.
• It is recommended to create Static and Rack Physical Groups with a maximum 40 devices for
applying an EPR.
• Make sure that the target devices are reachable to Power Manager and is responsive with respect to
the management protocols. Higher number of non-responsive devices or network latency can cause
performance impact while applying an EPR. For more information about the protocols used in Power
Manager, see the OpenManage Enterprise Power Manager User’s Guide available on the support
site.
• To disable the EPR’s, select a maximum of 200 EPR’s at a time for better performance and results.
8.2 Test Results in Scaled infrastructure (Devices and Groups)
Test results were very similar when the EPR actions were performed on Individual Devices, Static Groups
and Physical Groups.
The following graphs represent the CPU and Memory utilization of task execution service during different EPR
actions.