Without precise time synchronization, many network services will prove to be unreliable—or worse, they might fail. Here’s how you can synchronize time properly on your NetWare network.
Yesterday, I presented an article on correcting NetWare synthetic time errors. Ensure that such troubles don’t arise on your network by configuring the proper time.
Novell has developed a very reliable time synchronization scheme that requires all NetWare 4 or 5 servers to participate and be configured as time servers. When the server loads, TIMESYNC.NLM is loaded to manage time synchronization. TIMESYNC.CFG is used to store time synchronization settings. However, you can temporarily change these settings by issuing SET commands at the system console.
You can configure a NetWare server to be a single reference, reference, primary, or secondary time server.
Single reference servers
The first server installed into the tree will automatically become a single reference time server. The single reference server always believes that its time is correct, and it always believes that its time is synchronized with network time. The only other type of time server that can coexist with a single reference server is a secondary server.
Reference time servers?
A reference time server is normally configured on networks containing more than 30 servers, and it's important because it becomes the central time provider on the network. Further, it provides the time to primary and secondary servers.
A reference server cannot coexist with single reference servers or with other reference servers on the same LAN. While it is possible to have more than one reference server on a network, they should always be present at different sites in a WAN setting.
Primary time servers
Primary time servers are used to provide time to secondary servers and clients. To calculate the time they provide, primary servers poll the reference server and other primary servers for their time. A weighted average is calculated to determine the “correct” network time. If the calculated time is more than two seconds different from network time, the primary server changes its time 50 percent each polling cycle until its time is synchronized with network time.
Secondary time servers
Secondary time servers provide time to secondary servers and clients. They receive their time from single reference, reference, primary, or other secondary servers. Secondary servers believe that the time they receive is always correct.
Time servers communicate using either a configured list or the service advertising protocol (SAP). SAP is the default method of communication for time servers. However, SAP is considered a chatty protocol that can cause bottlenecks on slow WAN connections.
Configured list use
If you have a network that contains more than 30 servers or has slow WAN connections, you should use a configured list. The TIMESYNC.CFG file will contain the source from which the server will receive the time.
You can implement both configurations (configured list and SAP) for fault tolerance. However, remember that SAP can generate heavy network traffic.
As mentioned earlier, default NetWare settings dictate that the first server installed in the tree will be a single reference server, and all subsequent servers become secondary servers. These servers will use SAP to communicate network time to one another. No additional configuration is required as long as the network contains fewer than 30 servers, doesn’t have any slow WAN connections, and all of the servers use IPX. The default settings in NetWare will do everything for you. It doesn’t get any easier than that, does it?
What happens when your single reference time server goes down?
If the single reference time server should fail, one of the secondary servers can temporarily take its place. You can perform the operation by entering the following command at the system console: SET TIMESYNC TYPE = SINGLE. Just don’t forget to change the temporary single reference server back to a secondary server shortly before bringing the real single reference server back up. To do this, enter the following command at the system console: SET TIMESYNC TYPE = SECONDARY.
Unless you have a large network or slow WAN links, or you want to use IP, the default NetWare settings should be sufficient. The single reference server will happily provide time to the other secondary servers using SAP, and you can spend time doing something more interesting, like configuring that Quake server for play after 5:00 P.M.
Steve Pittsley is a desktop analyst for a Milwaukee hospital. He has a loving wife, three wonderful children, and enjoys playing drums, bowling, and most sports.There's no reason not to get exactly what you want from TechRepublic. By becoming a volunteer member of AdminRepublic's Virtual Advisory Board, you can help guide our Web site by giving us your opinions on the topics and features you need as an elite member of the admin community.Member responsibilities include:
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