Specifications

Hierarchy Relationships

LifeKeeper allows you to create relationships between resource instances. The primary relationship

is a dependency, for example one resource instance depends on another resource instance for its

operation . The combination of resource instances and dependencies is the resource hierarchy.

For example, since /usr1 depends on its operation upon the disk subsystem, you can create an

ordered hierarchy relationship between /usr1 and those instances representing the disk subsystem.

The dependency relationships specified by the resource hierarchy tell LifeKeeper the appropriate

order for bringing resource instances in service and out-of-service. In the example resource hierarchy,

LifeKeeper cannot bring the /usr1 resource into service until it successfully brings into service first the

disk and device instances.

Shared Equivalencies

When you create and extend a LifeKeeper resource hierarchy, the hierarchy exists on both the

primary and the secondary servers. Most resource instances can be active on only one server at a

time. For such resources, LifeKeeper defines a second kind of relationship called a shared

equivalency that ensures that when the resource is in-service on one server, it is out-of-service on the

other servers on which it is defined.

In the example below, the shared equivalency between the disk partition resource instances on each

server is represented. Each resource instance will have a similar equivalency in this example.

SteelEye Protection Suite for Linux47