Linux 2.0.36   RedHat 5.2

Problem description:
        Since several weeks we realized that some days, the system clock 
        of a dual pentium system goes back by 10/15 minutes some days,
        meanwhile other days the clock was correct.

        The same problem was discovered on a second dual Pentium system
        and reported to this forum.


Solution:
        According with  Clayton Weaver ([EMAIL PROTECTED]) we had two solutions
        to turn around this problem:

        1) assuming the hardware clock was uncorrected, use nist package
        2) assuming the hardware clock was correct, use hwclock

        The hardware clock is stable, this means in 10 days it didn't went back
        on both systems.

        We have introduced by cron on each hour the command
                hwclock --hctosys
        and both system clocks are now fine.

Feeling:
        The fact the system clock was degrading some days and not other days
        is probably due by the fact the days the system clock was corrupted
        the system executed heavy disk I/O night background tasks.

        Both systems have an internal adaptec scsi controller addressing
        4 9GB scsi disks. Then one system is using DPT controller meanwhile
        the second is using Mylex eXtremeRAID 1100 for RAID5 storage.

        Both systems are using the same network controller (3Com 3C905)

        My feeling is that the timer interrupts are delayed by some scsi driver
        interrupt handler.

        This is a copy of current /proc/interrupts:
         0:   16382786   timer
         1:       1643   keyboard
         2:          0   cascade
         8:          3 + rtc
        11:   10953720   eth0
        12:    1293394   aic7xxx
        13:    8687408 + IPI

Hope this will help 

Regards

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