HP Insight Control Software for Linux - Manual (Page 26)

1. Do I have sufficient power history collected for this system to make reasonable projections for
future behavior? Several months of power history will likely ensure that you are seeing a typical
depiction. However, if your computing demand has a seasonal component (such as the
holidays, tax season, or end-of-the-fiscal-year spikes), you may want to analyze power history
covering such time periods or allot additional headroom to avoid potential performance
impacts of the cap.
2. Applying a Dynamic Power Cap value allows sharing of the cap value dynamically from
systems that are idle to systems that are experiencing demand. However, a cap value applied
to a single system does not adjust automatically, so it is important to make sure that there is
sufficient headroom to avoid bumping into the cap when there is more demand in the future.
3. When considering the requirements for the future, what is the trend of my CPU utilization and,
therefore, power consumption and thermal output? Are my workloads relatively stable over
time, or is there a growing need for additional CPU? These factors dictate how much headroom
you must leave to avoid unnecessarily restricting performance.
4. Do I anticipate adding additional hardware (systems in an enclosure or memory, disks, or
add-in cards to a system)? Such additions will increase the upper end of the operating range
of the equipment.
5. Consider the business importance of the performance of an individual system before applying
any cap that is significantly below the Calibrated Max Power. If the response time of the
system is critically important, you must apply caps to other systems and make sure that your
critical systems always have access to the absolute highest performance they can deliver.
Task: Reclaiming power/thermal capacity for a new system
As you deploy the new system in your data center, you must select a location that has the following
resources:
•
Physical space in a rack to mount the system
•
Ample power delivery capacity to plug it into
•
Thermal capacity, or sufficient cooling, to avoid overheating it and surrounding systems
•
Network connectivity of the proper type and bandwidth
•
Proximity to other related systems and other organizational issues
If the power requirements for the system slightly exceed the power or thermal capacity within the
chosen rack, you can configure power capping to this system and others in the rack to make sure
that all systems get the necessary resources, without wasted allocation. If you are deploying a
system, you can apply the cap value to the enclosure that will include the system to ensure that the
power capacity of the power delivery devices and thermal capacity of the rack are not exceeded.
Then, insert the system in the enclosure. The cap value is divided among the other systems in the
enclosure. If it is not a system, you must determine the number of watts required by the new system.
You can use the HP Power Calculator, or for more accuracy, start the system and determine its
Calibrated Max Power. You can obtain this value from the Power/Thermal Analysis view or
Power/Thermal data report pages of power management. You can also obtain the value from the
Power Management Settings page of the system's iLO page, where it is mentioned as Server
Maximum Power, as shown below:
26 Managing power and cooling facilities in your data center