Hitachi Dynamic Link Manager Software Users Guide for Linux

Intermittent error monitoring can be used only when automatic failback has
already been enabled. The values that can be specified for intermittent error
monitoring depend on the values specified for automatic failbacks. For details
on how to specify the settings, see set (Sets Up the Operating Environment)
on page 6-15.
Intermittent Error Monitoring Actions
Intermittent error monitoring is performed on each path, and it automatically
starts as soon as a path is recovered from an error by using the automatic
failback function.
This subsection describes the following intermittent error monitoring actions:
• When an intermittent error occurs
• When an intermittent error does not occur
• When the conditions for an intermittent error to occur are changed during
error monitoring
When an Intermittent Error Occurs
When an error occurs on a path a specified number of times within a specified
interval, the error monitoring will finish and the path is determined to have
an intermittent error, upon which the path is removed from those subject to
automatic failbacks. The path that is removed will remain in the error status
until the online operation is performed. However, if the path satisfies certain
conditions (see
Figure 2-11 Path Status Transitions on page 2-24), it will be
subject to automatic failbacks and change to the Online status.
The figure below shows the action taken when an intermittent error is
assumed to have occurred on the path. For this example, the path is
determined to have an intermittent error when the error occurs 3 or more
times within 30 minutes. The events that occur are described by using the
time arrows.
Figure 2-13 Action What Will Happen When an Intermittent Error Occurs
on a Path
HDLM Functions
2-27
Hitachi Dynamic Link Manager (for Linux®) User Guide