====== Citrix XenServer and Power Management ======

See also **[[computing:power_mgmt|Power Management]]**

See also **[[https://www.sonoracomm.com/wiki/doku.php?do=search&id=xenserver|other XenServer pages in this wiki]]**

https://wiki.xenserver.org/index.php?title=Power_Management

http://www.ingmarverheij.com/damn-you-c-states-unexpected-xenserver-reboot/

http://support.citrix.com/article/CTX127395

:!: With newer XenServer versions, it is **no longer recommended to disable power management** in the server BIOS.

:!: Disable all power management in the BIOS:

  * AMD Power Now
  * Cool'n'Quiet
  * Intel SpeedStep
  * Enhanced Intel SpeedStep (EIST)

===== Get Power Managemment Status =====

On the XCP/XenServer host as ''root'':
 
<file>
xenpm get-cpufreq-states
</file>

No output indicates the (SpeedStep, PowerNow) power management has already been disabled. 

<file>
xenpm get-cpuidle-states | grep total | uniq
</file>

If C2 or higher is listed and there is time spent in that higher level state, this indicates that higher level C-states are still active. Check BIOS settings to disable the higher C-states. 

:!: A result above ''2'' indicates you need to disable power management in the BIOS.

===== BIOS Settings =====

:!: Disable all C-states, including C1E.

:!: If the server BIOS has power management options that leave power management to the BIOS rather than the operating system such as **Dell Active Power Controller** or **HP Power Regulator**, also disable this by setting the power management option to **OS Control**.

Dell:

  * Processor Settings -> Processor C-State Control
  * Processor Settings -> Processor C1E

HP:

  * Power Management Options -> Advanced Power Mgmt Options -> Minimum Processor Idle Power State -> No C-States
  * Power Management Options -> Advanced Power Mgmt Options -> Minimum Processor Idle Power Package State -> No Package State

Intel:

  * Advanced -> CPU Configuration -> Enhanced Intel SpeedStep Technology
  * Advanced -> CPU Configuration -> Turbo Mode (Turbo Boost)
  * Advanced -> CPU Configuration -> CPU C1E
  * Advanced -> CPU Configuration -> CPU C3 Report
  * Advanced -> CPU Configuration -> CPU C6 Report