[Gllug] Hardware problems / good replacements

James Courtier-Dutton james.dutton at gmail.com
Sat Feb 11 19:40:59 UTC 2012

On 10 February 2012 22:40, Phil Reynolds <phil-gllug at tinsleyviaduct.com> wrote:
> On 10/02/12 21:09, James Courtier-Dutton wrote:
>> In theory, stuff running in a VM should not mind what the actual hardware is.
>> The only thing I can think of that might be a problem is the system timer.
>> Maybe the VM is not keeping accurate time, so timeouts are happening
>> when they should not.
> Hmmm... how could I check for a system timer problem?

How far does it get in the boot process? Does it get as far as the command line?

Start with a PC that is keeping accurate time that you trust, using ntpd.
One way to check the timer is to just type "date" at the command line
in the VM and compare it the other trusted machine. Note the
difference, to the nearest second or two.
Then, wait about 10 mins and try it again, and see how far out it is that time.
If the difference is the same both times, you don't have a timer
problem, if the time is out, then there is your problem.
On problem machines, I saw the time drifting out by more than 10
seconds over a 10 minute period, so it is easy to spot.
If the time is your problem, you need to look at virtualised
clock-source drivers for inside the VM.

Kind Regards

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