<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Mar 23, 2015 at 5:42 AM, René J.V. <span dir="ltr"><<a href="mailto:rjvbertin@gmail.com" target="_blank">rjvbertin@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">To put it in context: my computers all use the same ntp server (<a href="http://fr.ntp.pool.org" target="_blank">fr.ntp.pool.org</a>) so that in theory they share the same clock. Turns out that my Mac is about 5min (a bit over 300 seconds) ahead of the others, and also of Bradley's VM. I've tried deactivating and reactivating (after setting time manually) network time in System Preferences, but it just jumps back to the future.<br>
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Is this related to the issue that was discussed a while back, and to Apple's conflicting service (pacekeeper?)?<br>
How can I set things right (other than doing a full reinstall of course ^^) ?<br></blockquote><div><br></div><div>Short version:</div><div><br></div><div><div style="font-size:12px"> sudo launchctl unload /System/Library/LaunchDaemons/com.apple.pacemaker.plist</div>
<div style="font-size:12px"> sudo rm /etc/ntp.drift</div>
<div style="font-size:12px"> sudo launchctl stop org.ntp.ntpd</div>
<div style="font-size:12px"> # wait an hour or so for ntpd to establish the current drift</div>
<div style="font-size:12px"> sudo launchctl load /System/Library/LaunchDaemons/com.apple.pacemaker.plist</div>
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<div></div><div> </div></div>(Which might or might not work; if it doesn't, you'll also need to unload Apple's ntpd and install some other one --- the MacPorts one works fine --- for the middle part, then restore Apple's because it has the bits that talk to pacemaker.)</div><div class="gmail_extra"><br></div><div class="gmail_extra">The longer version I'll briefly gloss: Apple replaced traditional ntp with one that uses less power and is more laptop friendly, when it works right. But it assumes that the clock drift of a brand new machine is the same as that of a fully burned-in and deployed machine, which it might well not be. The above commands are a "quick reset" of the clock drift, but as Apple removed some parts of ntp they may not be sufficient to determine the current clock drift; in that case, you need to use a full ntpd to characterize the drift, then switch back to Apple's for the improved performance and power management.</div><div class="gmail_extra"><br></div><div class="gmail_extra">(If your clock still drifts after that, file a radar with Apple. Replacing Apple's ntpd with a full one is probably not the best of ideas, although it can be done if needed. But full ntpd is not actually suitable for anything but certain scientific applications that require nanosecond accuracy; you pay quite a bit in CPU and power for that accuracy, and there are very few applications that require more than millisecond clock accuracy. One wonders how much better Linux etc. would perform if they didn't use full ntpd.)<br clear="all"><div><br></div>-- <br><div class="gmail_signature"><div dir="ltr"><div>brandon s allbery kf8nh sine nomine associates</div><div><a href="mailto:allbery.b@gmail.com" target="_blank">allbery.b@gmail.com</a> <a href="mailto:ballbery@sinenomine.net" target="_blank">ballbery@sinenomine.net</a></div><div>unix, openafs, kerberos, infrastructure, xmonad <a href="http://sinenomine.net" target="_blank">http://sinenomine.net</a></div></div></div>
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