[ntp:questions] NTP architecture with virtual machines for stratum-2 ?

janfrode at tanso.net janfrode at tanso.net
Mon Mar 4 19:55:19 UTC 2013

I have access to two external stratum-1 ntp-servers (one GPS and one with both GPS and long wave radio), and one company internal stratum-1/GPS, plus I'm considering if we should have a second company internal stratum-1. The external ntp-servers are hosted at trusted sister organizations.

So we have

* ntp1 (GPS, sister organization 1)
* ntp2 (GPS + radio, sister organization 2)
* ntp3 (GPS, company internal)
* ntp4 (not yet existing, do we need it? should we use something else than GPS?)

and I'm wondering how best to distribute time for our servers. We use Red Hat Enterprise Virtualization. with kvm-clock for most servers, and this seems to have been keeping very good time so far. Will it be safe to use virtual machines for stratum-2, and connect all servers to these ? 

Should our stratum-2 servers all be connected to ntp1-4, or is it better to have server1-ntp1, server2-ntp2, etc.. to make sure they don't all run off the same clock source? i.e. should we for server1 have ntp.conf with:

        server ntp1 prefer
        server server2 
        server server3
        server server4

        server ntp1 prefer
        server ntp2 
        server ntp3
        server ntp4

I can't point all our ntp-clients to the sister organizations stratum-1 servers, but I think our internal ntp1-appliances should handle the load of all our devices (a few thousand devices). Will it be best to point the ntp-clients to:

       server ntp3 prefer
       server ntp4 prefer
       server server1
       server server2
       server server3
       server server4

or just use the stratum2 servers?


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