Solaris Symptoms and Resolutions Article 19195

Last update: May 4, 2022 17:05 UTC (dbea9b7d4)

NOTE: This content is from SunSolve Article 19195 which once lived on the Sun Microsystems website.

SRDB ID	Synopsis	Date
19195	Upgraded to 2.6, using xntpd, but the system clock is drifting. Worked fine	4 Sep 1999

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Problem Description

Ever since upgrading to Solaris 2.6, the system clock has been drifting and there are messages like ‘synchronisation lost’, ‘Previous time adjustment didn’t complete’ and ‘time reset (step)’ a lot in the /var/adm/messages file. The system either was previously working fine with the freeware xntpd or the configuration was copied from another system that was using the freeware version.

– 23-Apr-99 08:22 US/Eastern –

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Problem Solution

The common lore for setting up xntpd on Solaris using the freeware version included the warning to set the kernel variable dosynctodr to 0 in the /etc/system file thus: set dosynctodr=0.

When using NTP on Solaris 2.6 or later, the kernel variable MUST be left at the default value of 1. Prior to 2.6 this variable controlled whether or not to rein in the softclock using the hardware clock, with the result that NTP and the hardware clock would fight for control of the soft clock; thus before 2.6 you had to set dosynctodr to 0. At 2.6, every system call that adjusts the softclock also sets the hard clock, thus while NTP controls the soft clock, the hard clock is also controlled. Setting dosynctodr to 0 reverts the behavior back to the pre 2.6 default behavior, having exactly the opposite effect as that intended.

Do not set dosynctodr to 0.

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Product Area: Bundled Network

Product: NTP

OS: Solaris 2.6

Hardware: Ultra 2

Document Content: with freeware xntpd.