31.4 Implementing Time Synchronization

As you plan to implement your time synchronization hierarchy, you should know how the OES NetWare and OES Linux product installations configure time synchronization on the network. Both installs key off whether you are creating a new tree or installing into an existing tree.

31.4.1 New Tree

By default, both the OES Linux and the OES NetWare installs configure the first server in the tree to use its internal (BIOS) clock as the authoritative time source for the tree.

Because BIOS clocks can fail over time, you should always specify an external, reliable NTP time source for the first server in a tree. For help finding a reliable NTP time source, see the NTP Server Lists on the Web.

OES Linux

When you configure your eDirectory installation, the OES Linux install prompts you for the IP address or DNS name of an NTP v3-compatible time server.

If you are installing the first server in a new eDirectory tree, you have two choices:

  • You can enter the IP address or DNS name of an authoritative NTP time source (recommended).

  • You can leave the field displaying Local Time, and the server is configured to use its BIOS clock as the authoritative time source.

    IMPORTANT:We do not recommend this second option because BIOS clocks can fail over time, causing serious problems for eDirectory.

OES NetWare

By default, the NetWare install automatically configures the Timesync NLM to use the server’s BIOS clock. As indicated earlier, this default behavior is not recommended for production networks. You should, therefore, manually configure time synchronization (either Timesync or NTP) while installing each NetWare server.

Manual time synchronization configuration is accessed at install time from the Time Zone dialog box by clicking the Advanced button as briefly outlined in Section 31.2.2, Choosing between Timesync and NTP (NetWare Only) and as fully explained in Setting the Server Time Zone and Time Synchronization Method in the OES NetWare Installation Guide .

31.4.2 Existing Tree

When a server joins an existing eDirectory tree, both OES installations do approximately the same thing.

OES Linux

If you are installing into an existing tree, the OES Linux install proposes to use the IP address of the eDirectory server (either NetWare or Linux) as the NTP time source. This default should be sufficient unless one of the following is true:

  • The server referenced is a NetWare 5.0 or earlier server, in which case you need to identify and specify the address of another server in the tree that is running either a later version of NetWare or OES Linux.

  • You will have more than 30 servers in your tree, in which case you need to configure the server to fit in your planned time synchronization hierarchy. For more information, see Section 31.2.3, Planning a Time Synchronization Hierarchy before Installing OES.

The OES Linux install activates the xntp daemon and configures it to synchronize server time with the specified NTP time source. After the install completes, you can configure the daemon to work with additional time sources to ensure fault tolerance. For more information, see Section 31.5.1, Changing Time Synchronization Settings on a SLES 9 Server.

OES NetWare

If you are installing into an existing tree, the OES NetWare install first checks to see whether you manually configured either NTP or Timesync time synchronization sources while setting the server Time Zone (see Setting the Server Time Zone and Time Synchronization Method in the OES NetWare Installation Guide ).

If you will have more than 30 servers in your tree, you should have developed a time synchronization plan (see Section 31.2.3, Planning a Time Synchronization Hierarchy before Installing OES) and configured your server according to the plan in the Time Zone panel.

If you haven’t manually configured time synchronization sources for the server (for example, if your tree has fewer than 30 servers), the install automatically configures the Timesync NLM to point to the IP address of the server with a master replica of the tree’s [ROOT] partition.