Controlling VCS Behavior at the Resource Level

This section describes how you can control VCS behavior at the resource level. Note that a resource is not considered faulted until the agent framework declares the fault to the VCS engine.

Resource Type Attributes

The following attributes affect how the VCS agent framework reacts to problems with individual resources before informing the fault to the VCS engine.

RestartLimit Attribute

The RestartLimit attribute defines whether VCS attempts to restart a failed resource before informing the engine of the fault.

If the RestartLimit attribute is set to a non-zero value, the agent attempts to restart the resource before declaring the resource as faulted. When restarting a failed resource, the agent framework calls the Clean entry point before calling the Online entry point. However, setting the ManageFaults attribute to NONE prevents the Clean entry point from being called and prevents the Online entry point from being retried.

OnlineRetryLimit Attribute

The OnlineRetryLimit attribute specifies the number of times the Online entry point is retried if the initial attempt to bring a resource online is unsuccessful.

When the OnlineRetryLimit set to a non-zero value, the agent framework calls the Clean entry point before rerunning the Online entry point. Setting the ManageFaults attribute to NONE prevents the Clean entry point from being called and also prevents the Online operation from being retried.

ConfInterval Attribute

The ConfInterval attribute defines how long a resource must remain online without encountering problems before previous problem counters are cleared. The attribute controls when VCS clears the RestartCount, ToleranceCount and CurrentMonitorTimeoutCount values.

ToleranceLimit Attribute

The ToleranceLimit attribute defines the number of times the Monitor routine should return an offline status before declaring a resource offline. This attribute is typically used when a resource is busy and appears to be offline. Setting the attribute to a non-zero value instructs VCS to allow multiple failing monitor cycles with the expectation that the resource will eventually respond. Setting a non-zero ToleranceLimit also extends the time required to respond to an actual fault.

FaultOnMonitorTimeouts Attribute

The FaultOnMonitorTimeouts attribute defines whether VCS interprets a Monitor entry point timeout as a resource fault.

If the attribute is set to 0, VCS does not treat Monitor timeouts as a resource faults. If the attribute is set to 1, VCS interprets the timeout as a resource fault and the agent calls the Clean entry point to shut the resource down.

By default, the FaultOnMonitorTimeouts attribute is set to 4. This means that the Monitor entry point must time out four times in a row before the resource is marked faulted.