[ntp:questions] ntp server specs

Chris Albertson albertson.chris at gmail.com
Wed Apr 20 23:43:02 UTC 2011

On Wed, Apr 20, 2011 at 2:07 PM, C BlacK <rblak at non.net> wrote:
> If I am setting up an ntp server for a lot machines, I have some questions.

Then you almost certainly want two NTP servers.  Ho9w else to do
scheduled maintenance, handle unscheduled down times or even know that
your NTP server is working correctly.   If NTP is important you need
at least two.  But no big deal as PC hardware is dirt cheap and used
re-purposed)  PC hardware works fine for this

As you are starting from scratch you can go with BSD.  (Although
recent versions of Linux work as well.)

What kind of reference clock will you be using?  A GPS receiver, a
pair of same (you will need access to the roof for an antenna) or
"pool" servers.  I'd go with "all of the above".  Again you need a way
to cross check.  With one clock you have no idea if it is even
'close".  With two how do you know which s right?  So have a plan.
There are many good plans but using pool servers is easy and free.
but you need your ow GPS with a PPS to build your local servers

> If the timing on client machines needs to be tight, should the ntp server be an x86 machine with a less than accurate clock
> or a ntp server with a very accurate clock.

Just keep the inside case temperatures reasonably constant.  Good
cooling and an air conditioned office is good enough

> I want the clients to track closely to server.

I think you need a more precise spec.  "closely" to some people means
seconds and to others micro seconds.  That is a million to one range.
A lot depends on the kind of network you have and the OS running on
your clients.  Windows just can't ever do as well as, say, BSD.  If
everyone is running a unix-like OS and connected with 100BaseT then
expect all of them to remain within a handful of milliseconds

There are ways of doing much better.  We handle telemetry and will use
IRIG for time distribution.  What to do and if NTP can evn work for
you depends on your definition of "closely".
Chris Albertson
Redondo Beach, California

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