Resource and Resource Group States and Settings

An administrator applies static settings to resources and resource groups. These settings can only be changed through administrative actions. The RGM moves resource groups between dynamic “states.” These settings and states are described in the following list.

• Managed or unmanaged – These are cluster-wide settings that apply only to resource groups. Resource groups are managed by the RGM. The scrgadm(1M) command can be used to cause the RGM to manage or to unmanage a resource group. These settings do not change with a cluster reconfiguration.

  When a resource group is first created, it is unmanaged. A resource group must be managed before any resources placed in the group can become active.

  In some data services, for example a scalable web server, work must be done prior to starting network resources and after they are stopped. This work is done by initialization (INIT) and finish (FINI) data service methods. The INIT methods only run if the resource group in which the resources reside is in the managed state.

  When a resource group is moved from unmanaged to managed, any registered INIT methods for the group are run on the resources in the group.

  When a resource group is moved from managed to unmanaged, any registered FINI methods are called to perform cleanup.

  The most common use of INIT and FINI methods are for network resources for scalable services. However, you can use these methods for any initialization or cleanup work that is not performed by the application.

• Enabled or disabled – These are cluster-wide settings that apply to resources. The scrgadm(1M) command can be used to enable or disable a resource. These settings do not change with a cluster reconfiguration.

  The normal setting for a resource is that it is enabled and actively running in the system.

  If you want to make the resource unavailable on all cluster nodes, disable the resource. A disabled resource is not available for general use.

• Online or offline – These are dynamic states that apply to both resource and resource groups.

  Online and offline states change as the cluster transitions through cluster reconfiguration steps during switchover or failover. You can also change these states through administrative actions. Use the scswitch(1M) command to change the online or offline state of a resource or resource group.

  A failover resource or resource group can only be online on one node at any time. A scalable resource or resource group can be online on some nodes and offline on others. During a switchover or failover, resource groups and the resources within them are taken offline on one node and then brought online on another node.

  If a resource group is offline, then all its resources are offline. If a resource group is online, then all its enabled resources are online.

  Resource groups can contain several resources, with dependencies between resources. These dependencies require that the resources be brought online and offline in a particular order. The methods used to bring resources online and offline might take different amounts of time for each resource. Because of resource dependencies and start and stop time differences, resources within a single resource group can have different online and offline states during a cluster reconfiguration.