[ntp:questions] Proposed NTP solution for a network

Ryan Malayter malayter at gmail.com
Thu Mar 5 14:18:07 UTC 2009


On Tue, Mar 3, 2009 at 7:21 PM, Jason <bmwjason at bmwlt.com> wrote:

> I'm pretty sure the appliance might be more capable than the LVC18, same
> manufacturer as many gov't agencies use, better antenna, highest grade
> coaxial cable from the antennas, etc. Has PPS and 10Mhz outputs. The
> problem is getting the PPS into the servers.

One thing you could experiment with is doing a sort of "poor man's
PPS" over Ethernet using broadcast NTP mode with the GPS devices as
servers and as short a poll interval as is possible. If all of the
blades are running the same hardware, kernel, and NTP versions, using
broadcast mode would result in NTP clients having essentially the same
timing information, and so they should behave as similarly as possible
within the limits of the hardware and environment.

Ntpd would still have to deal with the non-deterministic load and
thermal variations on each blade, of course, but such a scheme might
help with your goal of keeping all the blades as closely synced as
possible to each other. Obviously to address failure you would need
three or more GPS devices putting out broadcast packets in each
broadcast domain, using the prefer keyword on the clients to select
one as the leader of the pack.

Anyway, this is just an idea I had in the shower this morning. I am
sure the actual ntpd developers here will point out many reasons why
my scheme is not workable. However, it sounds as though you have the
resources to fully experiment with this - or any other proposed
solution - in a duplicate hardware environment, correct?

-- 
RPM



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