[CentOS] timekeeping on VMware guests

Les Mikesell lesmikesell at gmail.com
Wed Oct 14 19:07:20 UTC 2009


Brian Mathis wrote:
> On Wed, Oct 14, 2009 at 1:38 PM, James A. Peltier <jpeltier at fas.sfu.ca> wrote:
>> On Tue, 13 Oct 2009, Carlos Santana wrote:
>>
>>> Howdy,
>>>
>>> I am having time-drift issues on my CentOS VM. I had referred to
>>> following documentation:
>> The issue I had with time drift was due to running NTP inside the VM.
>> Don't do it.  The VM should get it's time through the VMWare tools that
>> are installed on the guest.  Once I did this the drift disappeared.
>>
>> --
>> James A. Peltier
> 
> 
> I recently wrote a script that retrieves the current time from an NTP
> server and compares it to the local time.  You may be surprised to
> know that inside of a VM the time is constantly drifting, and when it
> gets to 60 seconds difference, it is forcibly reset by vmware tools.
> In other words, this is a bad way to handle time.
> 
> As has been already mentioned, the timekeeping best practices from
> vmware have changed from using vmware tools to using NTP and correct
> kernel options (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427).
>  I have not yet implemented this myself, but it seems like a better
> way to handle it.

So is this going to change for CentOS when 5.4 is released?

Also, this seems geared towards guest settings when running under 
ESX(i).  The place I've seen the worst problem is when running under 
vmware server with a CPU that saves power by running at variable speed.

-- 
   Les Mikesell
    lesmikesell at gmail.com


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