Best Date-time setup for vmware virtual windows run on linux host?

[Bill Day-2]

Any thoughts on best Date-time setup for vmware virtual windows guests run
(without regular reboot) on linux host?

At http://geekswithblogs.net/TSCustomiser/archive/2007/04/05/a-z.aspx is
suggests:  "host receives the correct time from the network, and your
virtual machines receive the correct time from the host operating system."

I'm trying to see if W32Time service (like ntp for windows) should be
running at all. In our case, we'll be running an analytical instrument
from the virtual-windows on a linux host. And the windows-xp guest will
run typically weeks or even months without a reboot, and I'm wondering
what setup folks would suggest, so as to avoid drift, issues with DST,
etc. The "Timekeeping in VMware Virtual Machines.pdf" is somewhat
non-specific but does say:

To initialize the system time of day on startup, Microsoft Windows reads the batt-backed CMOS TOD 
clock. Occasionally, Windows also writes to this clock so that the time is approximately correct on the next 
startup. Windows keeps the CMOS TOD clock in local time, so in regions that turn their clocks ahead by an 
hour during the summer, Windows must update the CMOS TOD clock twice a year to reflect the change. Some 
rare failure modes can put the CMOS TOD clock out of step with the Windows registry setting that records 
whether it has been updated, causing the Windows clock to be off by an hour after the next reboot. If VMware 
Tools is installed in the virtual machine, it corrects any such error at boot time.

-Thanks,

  -- Bill Day

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[Joseph Tate-3]

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Windows W32Time is terrible, so don't bother with setting that up. I'd just install VMware tools and let the guest get it the time from the host. I've had no problems with this, but when running anything else in a vm, windows has had terrible drift, especially when leaving instances off for any period of time (W32Time only syncs about once a day), or suspending.

Joseph

On Tuesday 16 June 2009 10:32:21 am Bill Day wrote:
> Any thoughts on best Date-time setup for vmware virtual windows guests run
> (without regular reboot) on linux host?
>
> At http://geekswithblogs.net/TSCustomiser/archive/2007/04/05/a-z.aspx is
> suggests: "host receives the correct time from the network, and your
> virtual machines receive the correct time from the host operating system."
>
> I'm trying to see if W32Time service (like ntp for windows) should be
> running at all. In our case, we'll be running an analytical instrument
> from the virtual-windows on a linux host. And the windows-xp guest will
> run typically weeks or even months without a reboot, and I'm wondering
> what setup folks would suggest, so as to avoid drift, issues with DST,
> etc. The "Timekeeping in VMware Virtual Machines.pdf" is somewhat
> non-specific but does say:
>
> To initialize the system time of day on startup, Microsoft Windows reads th
>e batt-backed CMOS TOD 
> clock. Occasionally, Windows also writes to this clock so that the time is 
>approximately correct on the next
> startup. Windows keeps the CMOS TOD clock in local time, so in regions that
> turn their clocks ahead by an
> hour during the summer, Windows must update the CMOS TOD clock twice a year
> to reflect the change. Some
> rare failure modes can put the CMOS TOD clock out of step with the Windows 
>registry setting that records
> whether it has been updated, causing the Windows clock to be off by an hour
> after the next reboot. If VMware
> Tools is installed in the virtual machine, it corrects any such error at bo
>ot time.
>
> -Thanks,
>
> -- Bill Day

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[Bill Day-2]

Anyone tried the cpu-scaling fix:
http://blog.autoedification.com/2006/11/vmware-guest-clock-runs-fast.html

On Tue, 16 Jun 2009, Joseph Tate wrote:

> Windows W32Time is terrible, so don't bother with setting that up.  I'd just
> install VMware tools and let the guest get it the time from the host.  I've
> had no problems with this, but when running anything else in a vm, windows has
> had terrible drift, especially when leaving instances off for any period of
> time (W32Time only syncs about once a day), or suspending.
>
> Joseph
>
> On Tuesday 16 June 2009 10:32:21 am Bill Day wrote:
>> Any thoughts on best Date-time setup for vmware virtual windows guests run
>> (without regular reboot) on linux host?
>>
>> At http://geekswithblogs.net/TSCustomiser/archive/2007/04/05/a-z.aspx is
>> suggests:  "host receives the correct time from the network, and your
>> virtual machines receive the correct time from the host operating system."
>>
>> I'm trying to see if W32Time service (like ntp for windows) should be
>> running at all. In our case, we'll be running an analytical instrument
>> from the virtual-windows on a linux host. And the windows-xp guest will
>> run typically weeks or even months without a reboot, and I'm wondering
>> what setup folks would suggest, so as to avoid drift, issues with DST,
>> etc. The "Timekeeping in VMware Virtual Machines.pdf" is somewhat
>> non-specific but does say:
>>
>> To initialize the system time of day on startup, Microsoft Windows reads th
>> e batt-backed CMOS TOD
>> clock. Occasionally, Windows also writes to this clock so that the time is
>> approximately correct on the next
>> startup. Windows keeps the CMOS TOD clock in local time, so in regions that
>> turn their clocks ahead by an
>> hour during the summer, Windows must update the CMOS TOD clock twice a year
>> to reflect the change. Some
>> rare failure modes can put the CMOS TOD clock out of step with the Windows
>> registry setting that records
>> whether it has been updated, causing the Windows clock to be off by an hour
>> after the next reboot. If VMware
>> Tools is installed in the virtual machine, it corrects any such error at bo
>> ot time.
>>
>> -Thanks,
>>
>>   -- Bill Day
>
>

--
Bill Day

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