Fault management overview


Fault management overview
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A virtual business service allows high availability decisions to be localized at the cluster level, while it propagates the events up the dependency chain. It is not mandatory for Veritas Operations Manager to be online for the fault to be propagated and the configured behavior to be executed. The high availability of a virtual business service is guaranteed even if Veritas Operations Manager Management Server is temporarily down.

See Sample virtual business service configuration.

The following events can occur in response to a failure of the database application.

Each tier has its own high availability mechanism, such as Cluster Server or product_AppHA_long.
Inter-cluster fault propagation allows for the high availability events to be propagated up. For example, the virtual business service notifies the middle tier about the fault and any subsequent recovery that occurs in the database tier.
You can configure how a tier must respond to the fault in the lower tier. Depending on the business need, the upper tier might be configured to stop, restart, or stay online. The event might be propagated upwards based on the fault policy configured.

Table: Virtual Business Services fault policy behavior lists how a parent behaves in response to a fault or recovery on its child for various dependency types.

Table: Virtual Business Services fault policy behavior

Fault dependency type	Behavior
SOFT	When the child faults or recovers from the fault, the parent ignores the events. The parent does not take any action. This type of dependency is used when only start or stop ordering is required and no fault policy action is needed.
FIRM	When the child faults, the parent is taken OFFLINE. When the child recovers, the parent is brought ONLINE.
RESTART	When the child faults, the parent takes no immediate action. When the child recovers, the parent is taken OFFLINE and then brought ONLINE.

Fault dependency type

Behavior

SOFT

When the child faults or recovers from the fault, the parent ignores the events. The parent does not take any action.

This type of dependency is used when only start or stop ordering is required and no fault policy action is needed.

FIRM

When the child faults, the parent is taken OFFLINE.

When the child recovers, the parent is brought ONLINE.

RESTART

When the child faults, the parent takes no immediate action.

When the child recovers, the parent is taken OFFLINE and then brought ONLINE.

Table: Virtual Business Services fault propagation behavior list how a parent propagates a fault to its parents in response to a fault or recovery on its child for different dependency types.

Table: Virtual Business Services fault propagation behavior

Fault dependency type	Fault propagation
SOFT	When a parent gets notification about a child fault or a child recovery, the parent does not propagate this notification to its parents.
FIRM	When a parent goes offline as a result of a child fault, the parent propagates the fault to its parents. When a parent comes online as a result of a child recovery, the parent propagates the recovery to its parents.
RESTART	When a child faults, the parent does not immediately propagate the fault to its parents. When the parent is brought offline as a result of child recovery, the deferred fault is propagated to its parents. When the parent is subsequently brought online as a result of child recovery, the recovery is propagated to its parents.

Fault dependency type

Fault propagation

SOFT

When a parent gets notification about a child fault or a child recovery, the parent does not propagate this notification to its parents.

FIRM

When a parent goes offline as a result of a child fault, the parent propagates the fault to its parents.

When a parent comes online as a result of a child recovery, the parent propagates the recovery to its parents.

RESTART

When a child faults, the parent does not immediately propagate the fault to its parents.

When the parent is brought offline as a result of child recovery, the deferred fault is propagated to its parents.

When the parent is subsequently brought online as a result of child recovery, the recovery is propagated to its parents.

See Fault management for a virtual business service.