IBM SG24-5131-00 manual Resource Migration Types, Sticky Resource Migration

8.5.3.1 Resource Migration Types

Before performing a resource migration, decide if you will declare the migration sticky or non-sticky.

Sticky Resource Migration

A sticky migration permanently attaches a resource group to a specified node. The resource group attempts to remain on the specified node during a node failover or reintegration.

Since stickiness is a behavioral property of a resource group, assigning a node as a sticky location makes the specified resource group a sticky resource. Older sticky locations are superseded only by new sticky migration requests for the same resource group, or they are removed entirely during non-sticky migration requests for the same resource group. If it is not possible to place a resource group on its sticky location (because that node is down), the normal resource policy is invoked, allowing the resource to migrate according to the takeover priority specified in the resource group’s node list.

For both cascading and rotating resource groups, a normal resource policy means that other cluster nodes in the group’s node list are consulted at the time the sticky location fails to find the highest-priority node active. After finding the active node, cascading resource groups will continually migrate to the highest-priority node in the group’s node list (ultimately residing at the sticky location). Rotating resource groups stay put until the sticky location returns to the cluster.

You can attach the optional keyword sticky to any migration you perform, regardless of the resource group configuration (rotating or cascading). However, with very few exceptions, you always use the sticky location for cascading configurations, and do not use it for rotating configurations.

Non-Sticky Resource Migration

Resource groups on nodes not designated sticky are by default transient, non-sticky resources. These resources are temporarily placed on the specified node with the highest priority in the node list until the next failover or reintegration occurs. Non-sticky resources are best suited for use with rotating resource group configurations because of this transient behavior.

Because the normal behavior of cascading resources is to bound back to the highest available node in their node list, non-sticky migrations are usually not the best choice. The one instance in which a non-sticky migration of a cascading resource might make sense is if this resource has the

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