Re: [chrony-users] Chrony offset and stability adjustments?

[Stephen Satchell <list@xxxxxxxxxxxx>]

On 1/7/19 7:11 AM, LeBlanc, Daniel James wrote:
> The requirement that we are trying to meet is " Time accuracy must be within 1 ms of true time.", as described in Section 5.18 of https://www.nena.org/resource/resmgr/standards/NENA-STA-010.2_i3_Architectu.pdf.
> 
> I am currently connected to the NRC Internet-accessible time servers from our lab environment.  I am so close to meeting the spec (~1.3ms reported root dispersion) that I thought I would reach out to the experts to see if there was some adjustment that I might try.  :-)
> 
> I am running chrony within a virtual environment (VM) so have disabled rtcsync and enabled rtcfile within the .conf file.  I will look at reducing the maxclockerror and increasing the minsamples setting.  Any additional items to consider would be appreciated!

You say you are running your stuff in a VM.  Does the hardware host have
(1) ntpd or chronyd and (2) a very stable hardware clock?  Having your
VM object sync to that host-based NTP server should give you much better
dispersion.

You may also need to tweak the VM settings so that the VM's OS runs
frequently enough and with little jitter to keep the VM clock accurate.

What I found works is to let the host handle the time management, and
use a VM API call, or something like rtime(3), to fetch the current time
when you need it.

-- 
To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "unsubscribe" in the subject.
For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx 
with "help" in the subject.
Trouble?  Email listmaster@xxxxxxxxxxxxxxxxxxxx.