Detailed power information

The BladeCenter components that are part of each power domain are grouped by type. The information for power domain 1 is shown. There is a separate status page for each power domain in your BladeCenter unit. On this page, you also can configure power domain response to loss of power redundancy and view a graph of power consumption for the power domain (similar to the BladeCenter unit power graph). See Power Management.

The following information is displayed for each component that is installed in a power domain:

• Bay: This field displays the bays, if applicable, that a BladeCenter component occupies. It also indicates whether a blade server can reduce its power consumption (throttle) if power redundancy is lost.
• Status: This field displays an icon that indicates power-management events that are outstanding for the component. The icon indicates that a blade server will not be able to turn on because there is not enough remaining power in the power domain to support it. The icon indicates that a blade server is currently reducing its power consumption (power throttling) to maintain redundant power in a power domain.
• Module: This field displays the component description. Some BladeCenter components provide additional power information. The description of each component is a link that you can click to display a graph of additional detailed power information for the component. From the graph, you can select the types of power information that are shown: average power, maximum power, or minimum power. For blade servers, click the module name to display information about microprocessor performance.
  

  For blade servers that have power configuration capability, the management module displays fields that you can use to enable or disable power capping and to set the maximum amount of power that the blade server can use. These fields are not shown for blade servers that do not support these advanced features.

  
  The advanced management module displays information about allocated power and the power capping range for individual blade servers.

  • The allocated maximum power is a typical maximum power for various configurations. It is used by the advanced management module to determine whether a blade server will fit within the power budget of the domain. If the power budget has sufficient reserves to support the blade server, the management module will power-on the blade server.
  • The maximum power in the power capping range reflects the nameplate power for the blade server. This is not the same as the allocated maximum power.

  You can set the maximum power capping value for an individual blade server. This value, specified in watts, is the power value to which a blade server is capped by the advanced management module Power Management function. The maximum power capping value is persistent for all power cycles for blade servers.

  Some server blades, including the JS12 and JS22, support soft power capping. When this feature is supported, the web page will display both the range and the guaranteed range.

  • The Range is displayed as the soft capping minimum and capping maximum values.
  • The Guaranteed range is displayed as the capping minimum and capping maximum values. Previous releases of the advanced management module firmware referred to this as the capping range.
  Some server blades, including the JS12 and JS22, support Dynamic Power Saver, a power-saving mode that enables the blade server to selectively alter its operating voltage and frequency to reduce power consumption. See the blade server documentation for details. The following constraints apply to this feature.

  • The Dynamic Power Saver setting is displayed only when the blade server is powered on.
  • The Guaranteed range is displayed as the capping minimum and capping maximum values. Previous releases of the advanced management module firmware referred to this as the capping range.
  • You can not enable Static Low Power Saver and Dynamic Power Saver at the same time.
  • If the Dynamic Power Saver feature is not selected, the Favor Performance over Power check box is greyed out.

  Some blade servers support Dynamic Power Saver

  Note: The blade server must be powered-on for the power capping options to be available. If a blade server is removed from a BladeCenter unit or the BladeCenter unit is powered-off, the setting of the maximum power capping is lost.

  Average power consumption on a blade server frequently does not reach or exceed the minimum power capping threshold. The minimum power capping threshold represents a value that can be guaranteed under all operating conditions. Total power consumption on a blade server is related to conditions that can include both the hardware configuration and the applications that are running on the blade server.

  
• State: This field displays the power state of the module (On or Standby).
• Power in Use: This field displays the amount of power, in watts, that is allocated to the module. Usually, a module consumes less power than the maximum allocated power. Therefore the total power that is actually consumed by the BladeCenter unit might be less than the amount that is shown in this field.
• Maximum Allocated Power: This field displays the maximum amount of power, in watts, that a component requires. The maximum allocated power for modules is the worst-case amount that the module can consume, but the power-in-use number for some modules, such as I/O modules, the midplane, and the management module is the maximum allocated power when the module is powered-on. Usually, a module consumes less power than the maximum allocated power. Therefore, the total power actually consumed by the BladeCenter unit might be less than the amount that is shown in the Power in Use field.
• Minimum Allocated Power: This field displays the minimum amount of power, in watts, that a blade server requires when it is operating at its minimum power level (fully throttled).
• CPU Duty Cycles: This field applies only to blade servers. It displays the duty cycle of each microprocessor in a blade server, as a percentage of full operation. The duty cycles of the microprocessors are separated by commas. For each blade server that does not support or report its duty cycles, n/a is displayed. A duty cycle is a ratio of actual processing time that is expressed as a percentage of total available processor time. For blade servers, click the module name to display information about microprocessor performance.
• DOMAIN TOTALS: These fields list the total power that is allocated for all components in the power domain.

In this section, you can configure power management policy settings. The settings in this section apply to the entire BladeCenter unit, including the empty blade bays. You must have access to the BladeCenter unit and have either the Chassis Configuration role or Supervisor role to configure power-management policy settings. The settings are applied to each power domain independently. To ensure accurate reporting of power information, make sure that management-module firmware, blade server BIOS firmware, and Blade Systems Management Processor (BSMP) firmware are at the latest levels.

Blade server throttling achieves lower power consumption for a blade server by temporarily reducing the microprocessor performance. The advanced management module and the blade servers use power-management technologies that are built into certain microprocessors to throttle the blade servers to achieve lower power consumption.

Polices that enable throttling enable you to effectively use more total power from the BladeCenter unit, so that you can power-on more blade servers than would otherwise be possible. Blade servers might need to throttle to lower power consumption if a power module fails to keep the BladeCenter unit operational.

Note the distinction between ac power sources and power circuits. An ac power source is power that originates from a single power substation, such as a public power company, an on-site generator, or an uninterruptible power supply. A power circuit is power that comes from an ac power source and is limited by a circuit breaker. Having dual ac power sources means that you have power coming from more than one substation. Even though most server installations do not have this type of electrical setup, some of the policies are intended for use with dual power sources. You should have a dedicated circuit for each power module in your BladeCenter unit, regardless of the number of ac power sources that you have.

The name for the policy in effect for each power domain is a live link. Click a link to see a more detailed explanation of the policies, and to change the policy.

The following power management policies apply to the BladeCenter E, H, T, HT, and S units:

• Basic Power Management (default setting): This policy applies if the BladeCenter unit does not meet the recommended configurations for the other power policies. Blade servers power on, provided that the power that is consumed is less than or equal to the maximum total power limit for this policy. The total available power is higher for this than for other policies and is limited by the capacity of all power modules, up to a maximum of the BladeCenter unit power domain rating. The BladeCenter unit power domain rating might be lower than the total sum of all power module capacities. This is the least conservative policy for the BladeCenter unit power management.
  Note: If a power module fails, microprocessors on blade servers that are capable of throttling can throttle to reduce power consumption in the power domain. Power redundancy is not guaranteed and might result in the complete loss of power in the domain if the current power that is in use is higher than the capacity of the remaining power module.
• Power-Module Redundancy: This policy is intended for a single ac power source into the BladeCenter unit where each power module is on its own dedicated circuit. The maximum total power that is allocated within the power domain is limited to one less than the number of power modules when more than one power module is installed. One power module can fail without affecting blade server operation. Multiple power-module failures might cause all components within the power domain to power-off. Blade servers power-on only if they can operate unthrottled in case of power module failure. The number of blade servers that are able to power-on is determined by the maximum total power that is available from one less than the total number of power modules. If a single power module fails, all the blade servers that are powered-on will continue to operate at their unthrottled performance levels. If two or more power modules fail, the components within the power domain might power-off.
• Power Module Redundancy with Blade Throttling Allowed: This policy is intended for a single ac power source into the BladeCenter unit where each power module is on its own dedicated circuit. The maximum total power that is allocated within the power domain is limited to one less than the number of power modules when more than one power module is installed. Failure of one power module might cause blade servers to throttle, but the power domain would remain operational. Multiple power-module failures might cause all components within the power domain to power off. This policy enables the components to draw more total power than the power module redundancy policy supports. With this policy, it might be possible to power on blade servers that a more restrictive policy would prevent. A possible side effect is that blade servers might need to throttle to lower power consumption in the case of one power-module failure to keep the power domain operational. Blade server throttling achieves lower power consumption for a blade server by temporarily reducing the microprocessor performance. The management module and the blade servers use power-management technologies that are built into certain microprocessors to throttle the blade servers to achieve lower power consumption. Not all blade servers are capable of throttling. Blade servers are able to power-on, provided that the power consumed is less than or equal to the maximum total power limit for this policy. If a single power module fails, processors on blade servers that are capable of throttling, might throttle to reduce the power that is consumed to less than or equal to the rated capacity of the power modules. Blade servers power-on in a throttled state in some configurations. When power redundancy is restored, the blade server microprocessors return to their unthrottled performance levels.

The BladeCenter S unit supports two additional power-management policy options:

• AC Power Source Redundancy: This policy is intended for dual ac power sources into the BladeCenter unit. The maximum total power that is allocated within the power domain is limited to the maximum capacity of two power modules. This is the most conservative approach and is recommended when all four power modules are installed. When the BladeCenter unit is correctly wired with dual ac power sources, one ac power source can fail without affecting blade server operation. Note that some blade servers might not be able to power-on if doing so would exceed the maximum power limit of this policy.

• AC Power Source Redundancy with Blade Throttling Allowed: This policy is intended for dual ac power sources into the BladeCenter unit. The maximum total power that is allocated within the power domain is limited to the maximum capacity of two power modules. This is a conservative approach and is the best policy to use when all four power modules are installed. When the BladeCenter unit is correctly wired with dual ac power sources, failure of one ac power source might potentially cause some blade servers to throttle, but the BladeCenter unit remains operational. Note that some blade servers might not be able to power-on if doing so would exceed the maximum power limit for this policy. This policy enables components to draw more total power from the BladeCenter unit than the AC power source redundancy policy supports so that you can power-on blade servers that you might not otherwise be able to. A possible side effect is that in case of an ac power source failure, some blade servers might need to throttle to lower power consumption to keep the BladeCenter unit operational. Blade server throttling refers to achieving lower power consumption for a blade server by temporarily reducing the microprocessor throughput. The management module and the blade servers use power-management technologies that are built into certain processors to throttle the blade servers to achieve lower power consumption. Not all blade servers are capable of throttling.