[ntp:questions] Re: 15-second difference in time
heiko.gerstung_removeme_ at meinberg.de
Wed Aug 2 08:26:39 UTC 2006
> I've got a FreeBSD box acting as an ntp server for my local lan. All
> boxes connect up to it for synchronization of time. I run a network capable
> backup program called bacula and today while running a backup between two
> machines i got an error that the time between the two differed by 15
> seconds. I realize this isn't a lot of time, but reading the ntp docs i was
> under the impression that ntp would keep all boxes on my lan within
> milliseconds accurate of each other. If this is so i'd appreciate any
> suggestions as to what my issue might be.
We once had a customer using our LANTIME time servers on his database
backup servers. Each night the system clock of that server experienced
30-second-jumps and it turned out that he is using IDE/ATAPI harddisks
and DMA transfer (IIRC) and his Linux kernel was loosing timer ticks due
to the heavy I/O caused by nightly update jobs.
Sounds a little bit like your problem, doesn't it? :-)
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