Guest Time drift: Difference between revisions

Revision as of 14:05, 3 April 2012

Note: Article about Proxmox VE 2.0

Some tips if you have time drifts (mainly for windows)

Using the Real-Time Clock with Windows Server 2003 and Windows XP guests

Windows uses the both the Real-Time Clock (RTC) and the Time Stamp Counter (TSC).

For Windows guests the Real-Time Clock can be used instead of the TSC for all time sources which resolves guest timing issues.

To enable the Real-Time Clock for the PMTIMER clock source (the PMTIMER usually uses the TSC), add the following option to the Windows boot settings.

Windows boot settings are stored in the boot.ini file.

Add the following option to the end of the Windows boot line in the boot.ini file:

/usepmtimer

Add this to your vm configuration:

args: -no-hpet -no-kvm-pit-reinjection

then in your windows guest:

C:\Windows\system32>bcdedit /set {default} USEPLATFORMCLOCK on

@@ Line 26: / Line 26: @@
 ==WIN VISTA - WIN7 - WIN2008==
-Open the Windows guest.
+Add this to your vm configuration:
-Open the Accessories menu of the start menu. Right click on the Command Prompt application, select Run as Administrator.
-Confirm the security exception, if prompted.
+args: -no-hpet -no-kvm-pit-reinjection
-Set the boot manager to use the platform clock. This should instruct Windows to use the PM timer for the primary clock source. The system UUID ({default} in the example below) should be changed if the system UUID is different than the default boot device.
+then in your windows guest:
 C:\Windows\system32>bcdedit /set {default} USEPLATFORMCLOCK on