Hi, Dave-- On Dec 8, 2010, at 12:01 PM, Dave Cundiff wrote: > Hi everyone, > > I posted this to the forum as well but figured I'd try here since the > same people might not subscribe to both.
I'm not sure which forum you're mentioning here, although it proves you right about the conclusion you'd made here. :-) > I've been experiencing some terrible clock skew and just can't figure > it out. By terrible I mean I'm losing 30 minutes a day. The loss only > occurs when I bring the system under heavy load. The load is multiple > Rsync backups to a ZFS pool(with gzip compression) backed by a 16 disk > Raid50. I'm using a hardware Raid controller for battery backed write > caching. That kind of slew rate is well past what ntpd can deal with; it suggests possibly that you're losing timer interrupts, or maybe that the "time of day" clock on the motherboard is broken or dead. Output of "vmstat -i" might be informative for the former, for the latter check whether the BIOS can keep the clock sane while in the BIOS menu-- there should be a small Li battery on the motherboard which might be replaceable. You might also double-check that you've got the latest BIOS version update, but that's less likely to help. For a workaround, you can fire off "ntpdate -b" from cron every 5 minutes or similar to keep the clock from drifting too far. Regards, -- -Chuck _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
