Which Is Best?

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Solaris™ Operating Environment Boot Camp
By David Rhodes, Dominic Butler
Table of Contents
Chapter 19.  Time, Date, and NTP


Rdate is easy to understand and implement and, once the clocks are synchronized, should be accurate enough for most situations. The clock adjustment is harsh in that if the client's clock is incorrect, rdate will simply reset it. This can produce problems if the date needs to be set backwards, since log entries can become mismatched, which can cause problems with some applications.

NTP is more complex to understand, but once configured requires virtually no maintenance and each client will be very accurate relative to each other. The advantages are that a number of servers can be configured and if the main server is later upgraded from a local clock to a more accurate device, the clients will benefit without any alteration. Its clock adjustment is very sophisticated, ensuring that the clock is slowed down rather than shifted back in time. This means that things such as log file entries will always be in the correct order (i.e., chronological).

As an approximate guide, rdate should be accurate to within a second, whereas NTP should be accurate to within milliseconds. There are lots of factors that will vary these values, but it provides a good indication of the order of magnitude in accuracy between the two.

In our case, we will implement NTP, so we'll add the client configuration files to our "client directory" and use hydrogen as the main NTP server.


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    Solaris Operating Environment Boot Camp
    Solaris Operating Environment Boot Camp
    ISBN: 0130342874
    EAN: 2147483647
    Year: 2002
    Pages: 301

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