[ntp:questions] NTP under AIX?

William Unruh unruh at invalid.ca
Tue May 16 16:29:10 UTC 2017

On 2017-05-16, David Woolley <david at ex.djwhome.demon.invalid> wrote:
> On 16/05/17 16:37, Greg Moeller wrote:
>> Has anyone come across the advisability of running an enterprise-wide NTP server under an AIX LPAR?
>> We're currently running NTP on old Intel hardware and the company policy is to refresh hardware on a regular basis.
>> It seems a waste to buy several new servers if we could just put the NTP service on an AIX LPAR.
> If you are talking virtual machines, ntpd should always be run on the 
> host.  Any use on a guest should only be as a leaf node.

Remember also that you could put the ntp server onto some old or small
hardware (eg a Raspberry Pi connected to a GPS with a PPS output). These
is not necessity to run it on large fast expensive hardware. Also you
want to run it on something whose workload does not fluctuate since work
requires energy which produces heat, and the biggest enemy of accurate
clocks is fluctuating temperature of the clock crystal. The actual value of the temperature
does not really matter, but the fluctuations do.

But as David says, you should never try to run an ntp server on a
virtual machine. Far too much bad interaction between the virtual OS and
the actual hardware, which is what ntp is trying to control.

Of course it depends on the accuracy you want. If +-1sec is good enough
then almost anything you do will work. If you want +- 1 microseconds,
you will have to work at it and virtual machines will be a disaster. 
If you want 1ns, then you will need special hardware.

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