Messages in this thread | | | Date | Fri, 09 Apr 1999 18:32:15 +0200 | From | Eduardo Soriano <> | Subject | System clock goes back by 10 minutes a day / "SOLVED" |
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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 (cgweav@eskimo.com) 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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