Re: [gentoo-user] Server system date synchronizaion

[Alan McKinnon]

On 26/04/2013 19:11, Nick Khamis wrote:
>>> >> Thank you so much for your response, and I totally understand the
>>> >> effort vs. benefit challenge. However, is it really that much
>>> >> trouble/unstable to setup our own ntp
>>> >> server that syncs with our local isp, and have our internal network sync
>>> >> on it?
>> >
>> >
>> > No, it's not THAT much effort. You can get by with installing ntpd on a
>> > single machine, pointing it at the upstream time server and pointing all
>> > your clients to it. It's clearly recorded in the config file, you can't
>> > go wrong.
>> >
>> > It's understanding how this weird thing called time works that is the
>> > issue. Take for example leap seconds..... urggggggggggg...
>> >
>> > The basic question I suppose is why do you want to do it this way? What
>> > do you feel you will gain by doing it yourself?
>> >
>> >
>> > --
>> > Alan McKinnon
>> > alan.mckinnon@×××××.com
>> >
>> >
>> >
> Hello Alan,
>
> Thank you so much for your time. Our voip cluster time always vary for
> some reason....
> And with long distance, that could mean upwards to a dollar a call.


Ah, OK. That changes things quite a bit. I have a little bit of
experience with that - I work for a large ISP, we have a large VOIP
department and we run a stratum 2 time server that serves most of the
country.

First things first: you can't just stick any old upstream ntp server in
your config and walk away. You are then reliant on the quality of that
upstream, and far too often other time servers operate on a "good
enough" policy - if it's accurate to about a second, it's good enough
(and for desktop users i.e. most ISP clients, it is good enough).

I don't know how big your operation is, if you have budget I suggest you
invest in a proper master time source that is GPS-driven. We have a
Symmetricom (http://www.symmetricom.com) but it's a mature market with
several vendors. Shop around, prices are less than you'd expect (about
the same as a decent mid-range server and much less than Cisco's routers...)

Weather can get in the way, so back up the device with a decent second
upstream. I have a good one available run by the Science and Technology
Research part of the Dept of Trade and Industry and the third option is
all the other big ISPs around.

Depending on your accuracy needs you could get away without the GPS unit
and just use a good upstream, but I'd fight for the budget for it - tell
management it puts control of billing back in your hands, they always
fall for that one :-)

So the summary would be that I reckon ntpd will do what you want as long
as you chose good reliable time sources. With that in hand, the config
is easy as rather well documented. Shout here ont he list if you need a
hand with this when you come to deployment time




-- 
Alan McKinnon
alan.mckinnon@×××××.com