OSF DCE Administration Guide--Core Components

Managing the DCE DST
bound determined by the maxinaccuracy attribute setting, DTS forces the system to
synchronize until the inaccuracy is reduced to a level that is at or below the setting. Use
the maxinaccuracy attribute setting as a trigger for synchronization. You can vary the
setting to vary the tolerance of intersystem synchronizations, but be aware that, as the
setting becomes lower, network overhead rises. The default setting is 0.10 seconds (100
milliseconds).
The effects of the maxinaccuracy attribute setting on the system’s synchronization
behavior are the following:
1. The system’s clock value accumulates more inaccuracy than the maxinaccuracy
attribute value and DTS initiates a synchronization.
2. DTS computes a new time value.
3. DTS adjusts the system clock.
4. If the new clock setting still exceeds the maxinaccuracy attribute value, or if
clock drift later causes the inaccuracy to reach the value, the cycle is repeated.
Note that, if synchronization repeatedly fails to achieve an inaccuracy that is less than
the maxinaccuracy attribute value, the system can be continuously synchronizing. (See
Section 25.5.5 for information on how the syncinterval attribute prevents this loop.)
The default maxinaccuracy attribute value is designed to keep the system accurate
enough for most applications without being intrusive to network communications or
system processing. If your network includes one or more time-providers that ensure
extremely low inaccuracy, you can lower the maxinaccuracy attribute value. Raise the
value in the following cases:
• If a time-provider is not used in the network
• If a system is part of a WAN-only network configuration
• If the applications that call DTS do not require the level of precision achieved by the
default setting
The following example shows how to change the maxinaccuracy attribute value to 0.2
seconds:
dcecp> dts modify -change {maxinaccuracy 00-00:00:00.200}
25.5.5 The syncinterval Attribute
The syncinterval attribute prevents your system from synchronizing more often than the
specified interval. This attribute prevents the maxinaccuracy attribute from causing
continuous synchronizations. As mentioned in Section 25.5.4, the maxinaccuracy
attribute triggers system synchronization as long as the system’s inaccuracy is above a
specified value. The syncinterval attribute prevents synchronization from occurring
more frequently than the specified interval value. (The syncinterval attribute value is
randomized to prevent several systems from synchronizing simultaneously and is an
average rather than an exact value.)
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