On Tue, Sep 9, 2008 at 2:52 PM, Richard B. Gilbert <[EMAIL PROTECTED]> wrote: > FWIW, a system that has been > synchronized by NTP will tend to stay close to the correct time for a > reasonable period of time as long as the environment does not change > significantly. If the network fails AND the air conditioning fails you > are in trouble!
That is, of course, precisely what happens in many long-term power outages. Typical UPS battery run times in a datacenter are in minutes, not hours. And UPS rarely backup the cooling system. If you don't have a working generator on standby with plenty of fuel, you're up the proverbial creek. Even if you have the generators, you have to be careful. A colocation provider recently had an outage that was interesting. A truck ran into their (exterior) transformers, cutting utility power. No problem, they have generators, right?. Well, their water chillers could not re-start fast enough after the generators came on line, so the rapidly increasing temperature caused shut down about 1/3 of the servers in their datacenter. All told, their SLA credits amounted to millions of dollars. Focusing on extreme redundancy for one piece of your infrastructure (time) is sort of pointless if you don't have full tested redundancy in the lower layers of the system (physcial plant, power, cooling, network, etc.) -- RPM _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
