Parallels H-Sphere Documentation System Administrator Guide


Server Time Synchronization


Last modified: 07 Apr 2005


WARNING: This documentation covers Parallels H-Sphere versions up to 3.1. For the latest up-to-date Parallels H-Sphere documentation, please proceed to the official Parallels site.

This document explains how to automate adjusting your servers' time through Network Time Protocol (NTP). Server time synchronization prevents various errors that you are likely to run into unless your servers' time is correct. Automation of server time synchronization is implemented through setting up crontab task for your NTP client.

To automate adjustment of your servers' time through NTP, do the following:

  1. Make sure you've got an NTP client software installed on your server(s).
    * If not, download it from
  2. Choose time server(s) and add it to your NTP client configuration.
  3. Log into your servers as root and use the "crontab -e" command to add an NTP cron task.
    In the following example your server time is checked with a time server every 4 hours:

    # date syncronization
    0 */4 * * * /usr/sbin/ntpdate ntps1-{0,1,2}


NTP Time Servers

The following links will take you to the lists of time server hosts to choose from.

To find the time servers that best suit your server location and other requirements go to

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