Date: Fri, 21 Dec 2007 13:24:40 -0500 From: Bill Moran <wmoran@potentialtech.com> To: John Webster <jwebster@es.net> Cc: questions@freebsd.org, "Michael W. Lucas" <mwlucas@blackhelicopters.org>, shinny knight <sh1nny_kn1ght@yahoo.com> Subject: Re: timekeeping on jail servers Message-ID: <20071221132440.31ded74f.wmoran@potentialtech.com> In-Reply-To: <7BEE288E7C218E96DB9E8AA0@jw-laptop.dhcp.lbnl.us> References: <20071218165521.GA37529@bewilderbeast.blackhelicopters.org> <343753.78466.qm@web44811.mail.sp1.yahoo.com> <20071221112303.19619c39.wmoran@potentialtech.com> <7BEE288E7C218E96DB9E8AA0@jw-laptop.dhcp.lbnl.us>
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In response to John Webster <jwebster@es.net>: > > --On December 21, 2007 11:23:03 AM -0500 Bill Moran <wmoran@potentialtech.com> wrote: > > > In response to shinny knight <sh1nny_kn1ght@yahoo.com>: > > > > The reason that is not recommended is that it results in sudden steps > > of the clock. Occasionally, these steps go backwards. Software that > > is very sensitive to time changes (make processes, database servers, > > anything doing calculations WRT time) can break, crash, or work > > inaccurately. > > ntpdate -B should slew the time slowly. (According to the manpage.) Not generally suitable for cron because it can take longer to slew than it does for the next cron execution to occur, which would then result in multiple ntpdate programs fighting each other (not sure what the effect of this would be). If you ask me, the -B option is available for people who want to totally hose timekeeping on their system. -- Bill Moran http://www.potentialtech.com
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