Thanks, David. That's the kind of thing that I'd like to be able to
display...pictures telling 1000 words, etc.
Ultimately, we're talking about linux (CentOS 6/7) running on modern
multi-core hardware vs similar specs under some existing VSAN clusters (ESX
6).
As I mentioned, it's intended as a stratum2 setup with a pair of logical
hosts in each of multiple locations, served both via an anycast VIP from
each site for "good enough" clients (potentially many thousands of them) and
via a DNS pool for true ntpd-based clients that support quorum. The latter
will likely number in the high hundreds or low thousands. The pool and
anycast setups are intended to allow horizontal scaling of the service as
clients from more sites leverage it.
There's little doubt that qualitatively, the hardware servers will give
better results, but the folks that manage the OpEx want to be able to
quantify the negative impact that being on VMs might introduce. i.e. is it
worth taking on the incrementally more expensive cost of 20-some server
chassis to get the performance/accuracy increase over a similar number of
VMs.
Do you mind sharing how you plotted the linked graphs?
Dan
==========================
Dan,
I'm glad you found that helpful - I'm a great fan of graphical presentation!
As my virtual machine experience is limited to running Linux and XP on a
desktop system, I'm unqualified to advise on the much more sophisticated
setups you are considering, and anyway my experience is mainly Windows.
Fortunately, though, the plotting tools I use are based on MRTG (written in
Perl) and a couple of Perl scripts which parse the output of "ntpq", so they
should run equally well on Linux. I've written it all up here (some time
back):
http://www.satsignal.eu/ntp/NTPandMRTG.html
I also have a couple of Windows programs for monitoring NTP on multiple
servers.
Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: [email protected]
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