[ntp:questions] Correcting a large time difference
unruh at wormhole.physics.ubc.ca
Sat Jul 31 15:51:53 UTC 2010
On 2010-07-31, David Woolley <david at ex.djwhome.demon.invalid> wrote:
> Richard Heritage wrote:
>> I've inherited a RHEL 5 server that isn't running ntp and whose clock
> is about 30 minutes fast. What I would like to do is start ntpd & have
> it gradually correct the clock. I don't care how long it takes--it's
> been running this way for months. The server runs an email application
> that may be sensitive to a large backward jump in the clock, and leaving
> the server down for a half hour isn't a good option.
> Do not run ntpd. Use ntptime to set the tickadj value to give the
> highest acceptable slew rate (granularity is typically 100ppm). Reset
> it to normal as you approach the zero crossing. Measure the residual
> frequency error and calculate the ntp.drift value for it. Set that
> value in ntp.drift and start ntpd.
> ntptime goes by other names on some systems.
adjtimex on Linux systems.
> PS Please don't write your paragraphs all on one line. There are proper
> ways of representing wrapped text in MIME email.
More information about the questions