Hello,
Introduction: At our company we have 50+ hosts, most of them are virtual (Xen) servers, having a limited number of physical machines available to be an NTP server. We're a small telecom company and we prefer to have the same time in all of our hosts (time island), rather than an absolutely accurate time. Current configuration: Our normal config is with 2 prefered IPs (same server, not dedicated to NTP) and 2 non-prefered external hosts (either from the pool or some selected server). In some cases there aren't external hosts. We just use server peers: no peer connections, no multicast and no broadcast. This NTP server is also used by our internet clients. We monitor 3 parameters of the NTP service: offset, reference peer (server) and active peers. But this configuration has some problems for us: - Once in a while we get warning offsets, mainly when one of our external peers goes insane and we get 30+ ms offsets, when we normally have less than 1 ms, having spikes that can go to 10-15 ms. With this, our goal of having "the same time in all of our hosts" is compromised; - Also with little frequency one or many of our hosts loose a reference peer, like yesterday, when 2 external peers (in the pool) got an offset of ~1000 ms, having many of our hosts having 2 good peers (our internal server) and 1 or 2 rejected peers (with ~1000 ms offset); - Obviously, if we do some maintenance in our server, of if it has a problem, and then we get some problems in our ntp network, having clients without reference clock and/or with bad offset when the server returns to life; - Our goal of having excellent synchronization between our hosts isn't achieved. The question: Given that, or ignoring what I've said, what are your recommendations? . How many peers to configure for each client, at least? Only one (the same for all)? or a higher number? . Should we keep preferred servers, having alternatives? . Should we use peer connections? . Are broadcast or multicast better options? . Could we use virtual servers as internal alternatives in the network? . Pool servers aren't available everywhere, but are they good options? Our server is configured with 4-5 delay stratum 1 external servers with 60-70 ms of delay (preferred), and 2 or 3 external servers with stratum 2+ with <5 ms of delay (not preferred). Is that a good option? Thank you all, Nuno Pereira Software engineer at G9Telecom
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