[blfs-dev] NTP

Matthew Burgess matthew at linuxfromscratch.org
Thu Feb 16 04:38:41 PST 2012


On Thu, 16 Feb 2012 11:16:12 +0000, Andrew Benton <b3nton at gmail.com> wrote:
> On Wed, 15 Feb 2012 18:47:37 -0800
> Qrux <qrux.qed at gmail.com> wrote:
> 
>> 	* So, I propose turning -x off.
> 
> I agree, I run ntpd -g
> However, I also think the ntpd bootscript will work fine for most
> people and for those (like me) who think it should be done differently
> it's trivial to edit the bootscript; your distro, your rules and all
> that ;)

It probably doesn't affect many LFSers, but Oracle's RAC installation/
configuration wizard explicitly checks for '-x' in the ntpd options.

It does this because you really don't want your database server's time
from jumping backwards, and '-x' (or 'tinker step 0' in /etc/ntp.conf)
is the only way to guarantee that won't happen.  Interestingly,
apparently Dovecot doesn't like time going backwards either; I'm sure
there are other servers that prefer a uni-directional arrow of time too.

For more 'normal' setups, I'd agree that calling 'ntpd -g -q' to do an
initial time sync at bootup, followed by ntpd without any other options
would be sufficient; the odds that the ntp pool servers most people use
are going to jump backwards are so small, I don't think it's worth
guarding against by using the '-x' option by default.

Regards,

Matt.




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