Does anyone know the interval in which OS X Snow Leopard syncs with Internet time? Is it more than once-a-day? Every hour? I'm trying to set the same interval with a Windows server which is also syncing to time.apple.com but is only set to sync every 7 days which is way to far between syncs.
Thanks in advance.
Kyle
Mac Pro, Mac OS X (10.6.8), Mid-2010 Mac Pro
Actually I don't think it ever tries to resync after booting. It may do it during booting however.
The only sure way to resync is to open the Date&Time preferences and toggle the Set date and time automatically. It may be that just launching the Date&Time prefs is sufficient.
I may be wrong about this so I'd be happy to be corrected. But this is the way I feel it has always worked.
(missed the 15 minute timout to update my post)
I know that the ntpd daemon is running but I am not sure it does periodic time server checks. On the other hand why have it running if it doesn't?
Yeah. I assume if ntpd is running it's gotta update at some point. Imagine if your machine is on 24/7. I updated my Windows boxes to update every 12 hours for now. Fairly simple through the Windows regedit.exe and restarting Windows Time service. I also assume there is some registry file that you can manipulate to change the schedule for the Mac OS? That registry entry would probably state the interval as well...
kyleit wrote:
Does anyone know the interval in which OS X Snow Leopard syncs with Internet time?
No clue. But I believe the job is done by ntpd (the NTP daemon); and I believe (but I may be quite wrong) that ntpd uses some funky algorithm to determine how often to run -- it's nothing as simple as a repeating interval. You can read additional details in the ntpd(8) manpage. Note, section 8, not section 1, so it's
$ man 8 ntpd
not
$ man ntpd
manpage doesn't really show a whole lot of useful data. I'll have to give Support a call and see if there's a real schedule somewhere as well as a way to modify it if needed.
Anyone else feel free to chime in if you know the schedule interval or config file!
same problem, on Leopard...
I was seeing on Little Snatch some "ntpd" and all the time is syncing or something with time.apple.com
Why It needs to do that all the time?
Open Console, choose "All Messages," & then filter on "ntpd." That should show you when the ntpd process resets the time as well as when it can't rech the server.
Checking the Console is very sporatic. Some machines show a sync each day and some don't show anything. I believe this to be happening when the machine is powered on or waking from sleep, as the machine that shows its sync daily is a laptop that is waking up from a sleep every day around the same time, and the machines that aren't showing any sync are left on for days at a time.
This sync is mission critical as the server we access (Avid ISIS) requires all clocks to be in sync within 1-2 seconds in order for file sharing to work. One client cannot write a file that is timed a few seconds later than another client trying to look at it. To the 2nd client, the file doesn't exist yet...
Anyone found a way to set the interval yet? I'd like to set it to every 6 hours as this seems like a good period of time when the clocks can stay in tune.
Called Apple a week ago but haven't heard anything back from them yet.
The log will only show when the time is reset, not every time the daemon contacts the NTP server.
As fane_j mentioned, ntpd does not work on a set interval; instead complex algorithms determine how often it does that. Extensive documentation for the ntp program can be found on your Mac in the /usr/share/doc/ntp/ folder. It's in html format, so you can read it using a browser. I suggest starting with the /usr/share/doc/ntp/index.html file. That is in effect the home page & everything else is hyperlinked to that.
There is a configuration file, normally located at path /private/etc/ntp.conf, but as you will see from the documentation, modifying it is not as simple as you might think, nor should you try to do that without understanding all the implications that has on network operations, security, local clock accuracy, & such.
If nothing else, read the "How NTP Works" section in /usr/share/doc/ntp/notes.html
Anyway, assuming you have a good Internet connection, your Mac(s) should maintain accurate enough time for your purposes without changing anything. The same may not be true for the Windows machines. See the "Microsoft Windows" section of the Wikipedia Network Time Protocol page for more about why that may be so.
Clock Sync Interval
