See also Power Management
See also 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:
On the XCP/XenServer host as root
:
xenpm get-cpufreq-states
No output indicates the (SpeedStep, PowerNow) power management has already been disabled.
xenpm get-cpuidle-states | grep total | uniq
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.
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:
HP:
Intel: