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On 26/04/2013 20:36, Stroller wrote: |
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> |
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> On 26 April 2013, at 16:41, Alan McKinnon wrote: |
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>> ... |
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>> So here's what you do: sync everything to your ISP's time servers. |
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>> Chances are good they do a better job than you can, just like with DNS |
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>> caching. |
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> |
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> |
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> I'm not sure if my ISP offers time servers, but Apple and MS both run time servers which are publicly accessible (presumably from any o/s). |
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> |
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> I've never changed my laptop from its default, to sync with time.euro.apple.com, but my Linux boxes all use the public ntp pool, so I was surprised to read the other comments claiming the latter to be inaccurate. |
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> |
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> Whenever I restart /etc/init.d/ntpd on my Linux boxes I can see their time match that of my laptop, as consistent as I can see, i.e. less than a second's difference between them. |
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ntpd has some wicked amazing optimizations built in, much more so if you |
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use multiple upstream sources. If one of them drifts, the software is |
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able to recognize it and defer instead to other sources that seem more |
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stable. It's like magic, the dodgy data tends to fall out of the system |
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leaving just the good data. Which is exactly what you want when using |
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volunteer resources of unknown and variable quality. |
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I'd compare the public ntp pool to a privateer race team - they can be |
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awesome, do amazing things with limited resources and often win races. |
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But for consistency and the best of the best, you need the Honda and |
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Yamaha factory teams (complete with obscene budgets). |
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For laptop, desktop and even most company's server needs, the public ntp |
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pool is perfectly good enough, which is what I think you observe in your |
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environment. |
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-- |
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Alan McKinnon |
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alan.mckinnon@×××××.com |
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