Technical data

Setting System Time
6.9 Using SYSMAN to Manage System Time
6.9 Using SYSMAN to Manage System Time
You can manage system time for an OpenVMS Cluster system with SYSMAN
CONFIGURATION commands. Table 6–5 summarizes these CONFIGURATION
commands and their functions.
Table 6–5 SYSMAN CONFIGURATION Commands
Command Function
CONFIGURATION SET TIME Updates system time
CONFIGURATION SHOW
TIME
Displays current system time
6.9.1 Modifying the System Time
Use the CONFIGURATION SET TIME command to modify system time for nodes
in an OpenVMS Cluster system, as well as for individual nodes. You can specify
time values in the following format:
[dd-mmm-yyyy[:]] [hh:mm:ss.cc]
You can also enter delta time values. Refer to the OpenVMS User’s Manual for
more information about time formats.
In a cluster environment, SYSMAN sets the time on each node to the value you
specify. However, if you do not specify a value, SYSMAN reads the clock on the
node from which you are executing SYSMAN and assigns this value to all nodes
in the cluster. In a remote cluster, SYSMAN reads the clock on the target node in
the cluster and assigns that value to all nodes. Note that the time-of-year clock
is optional for some processors; refer to your processor’s hardware handbook for
more information.
SYSMAN tries to ensure that all processors in the cluster are set to the same
time. Because of communication and processing delays, it is not possible to
synchronize clocks exactly. However, the variation is typically less than a few
hundredths of a second. If SYSMAN cannot set the time to within one-half second
of the specified time, you receive a warning message that names the node that
failed to respond quickly enough.
As a result of slight inaccuracies in each processor clock, times on various
members of a cluster tend to drift apart. The first two examples show how to
synchronize system time in a cluster.
Examples
1. The following procedure sets the time on all cluster nodes to the value
obtained from the local time-of-year clock, waits 6 hours, then resets the
time for the cluster:
$ SYNCH_CLOCKS:
$ RUN SYS$SYSTEM:SYSMAN
SET ENVIRONMENT/CLUSTER
CONFIGURATION SET TIME
EXIT
$ WAIT 6:00:00
$ GOTO SYNCH_CLOCKS
6–24 Setting System Time