When the ntpd on aeron has lost sync 2003-2006.


    The ntp daemon keeps time on the aeron cpu by communicating with time servers on the ao net. The  message log /var/ntp.log tells when events occurred (status monitoring has not been enabled). To check how the clock is performing the ntp.log file for 13may03 through 30mar06 was searched for "synchronization lost" events.
    The plot shows when the   nptd clock synchronization was lost (.ps) (.pdf):

    Looking at the log file, the synchronization lost events are occurring when the clock had drifted off. On the wapps (see ntpd on wapps, and wapp clock drift), the local clock would drift when the local cpu was busy. So something is causing the aeron cpu to be busy around 4 am:

Cron jobs on aeron:

    The crontab for aeron was:
min hour day of
month day of
script dir
01 * * * * /etc/cron.hourly
02 4 * * * /etc/cron.daily
22 4 * * * /etc/cron.weekly
42 4 1 0 /etc/cron.monthly
The problems around 4:20 to 4:40 could be cron.daily scripts that had not finished by 4:20 or cron.weekly scripts that started at 4:22.
    A plot of the time difference between time resets (.ps) (.pdf) shows lots of time resets spaced by 1 day but only one spaced by a week). So the problem is the cron.daily script. The cpu hog of the cron.daily is probably the slocate.cron that scans and indexes the entire files system. It wasn't failing till around 4:20 probably because the routines run before it took awhile.


processing: x101/ntp/aeronLosesSync.pro