White Paper

Dell Power Center’s Power Policies for 12
th
-Generation Servers
9
Static capping in Power Center Figure 4.
Group capping value
Capping value for each server
Dynamic Capping
Due to changes in workload(s), the power demand of each individual server can vary greatly and static
capping on an individual server basis may not be the best policy as it does not allow a server’s power
allocation to grow where power is available, resulting in artificial restriction of the system’s
performance. Unlike static capping, dynamic capping adjusts the capping values of each server in a
group, based on the power demand of the server versus the total power allocated and available to the
group. Dynamic capping’s responsive distribution of power helps to minimize the negative impact to
performance.
Dynamic capping is built upon measurement-driven profiling and uses a multi-tiered algorithm to
actively adjust the capping values at set intervals. At each sampling interval, Power Center collects
the power consumption data from each server. It analyzes the data and, considering the priority
setting of the server, adjusts the capping value of each server if power can be reallocated. It raises
the power caps of individual servers that are busier and need more power, while lowering the caps for
the servers that are not using their total allocated power budget. This balances the group capping and
optimizes the use of power among the servers in the group. Note that power is not typically taken from
lower-priority servers using their total power budget cap in order to give power to higher priority