| Re: [chrony-users] Chrony offset and stability adjustments? |
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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Chrony offset and stability adjustments?
- From: Denny Page <dennypage@xxxxxx>
- Date: Mon, 7 Jan 2019 09:28:50 -0800
- Cc: "LeBlanc, Daniel James" <daniel.leblanc@xxxxxxxxxxxxx>
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I don’t believe a guarantee of < 1 ms from true time is achievable inside a VM. Too many things happen in a VM system even when the host is not over subscribed.
For a few hundred dollars you can buy a small hardware device that serves NTP (or even PTP) based on GPS. Very, very cost effective.
Denny
> On Jan 07, 2019, at 07:11, LeBlanc, Daniel James <daniel.leblanc@xxxxxxxxxxxxx> wrote:
>
> Hi Miroslav.
>
> 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!
>
> Thanks.
>
> Daniel J. LeBlanc, P.Eng., MBA, DTME | Senior Network Architect | Bell Canada
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