[CentOS] system date using ntp client is drifting

From: Arun Khan <knura9 at gmail.com>

> On Tue, Jun 5, 2012 at 1:57 AM, Nate Duehr <denverpilot at me.com> wrote:
>>  After getting the clock in sync, "hwclock --systohc" to push it 
> into the CMOS clock.
> 
> +1
> 
> On a PC Engines ALIX board (no battery backup for CMOS) that I am
> using as an WiFi AP, I have had to resort to a similar trick.  Once at
> boot up and then every 20 mins from the system crontab.

/etc/sysconfig/ntpd:
  # Set to 'yes' to sync hw clock after successful ntpdate
  SYNC_HWCLOCK=yes

JD