Relationship Between Resource Groups and Disk Device Groups

The following information applies to this update release and all subsequent releases.

HAStorage and HAStoragePlus Resource Types (5/02)

The following change was introduced in the Sun Cluster 3.0 5/02 update release and applies to this update and all subsequent updates to Sun Cluster 3.0 software.The resource types HAStorage and the HAStoragePlus can be used to configure the following options.

• Coordinate the boot order of disk devices and resource groups by causing the START methods of the other resources in the same resource group that contains the HAStorage or HAStoragePlus resource to wait until the disk device resources become available

• With AffinityOn set to True, enforce colocation of resource groups and disk device groups on the same node, thus enhancing the performance of disk-intensive data services

In addition, HAStoragePlus is capable of mounting any cluster file system found to be in an unmounted state. See "Planning the Cluster File System Configuration" in the Sun Cluster 3.0 12/01 Data Services Installation and Configuration Guide for more information.

If the device group is switched to another node while the HAStorage or HAStoragePlus resource is online, AffinityOn has no effect and the resource group does not migrate along with the device group. On the other hand, if the resource group is switched to another node, AffinityOn being set to True causes the device group to follow the resource group to the new node.

Recommendations (5/02)

The following change was introduced in the Sun Cluster 3.0 5/02 update release and applies to this update and all subsequent updates to Sun Cluster 3.0 software.

To determine whether to create HAStorage or HAStoragePlus resources within a data service resource group, consider the following criteria.

• Determine whether to use HAStorage or HAStoragePlus.

  • Use HAStorage if you are using Sun Cluster 3.0 12/01 software release or earlier.

  • Use HAStoragePlus if you are using Sun Cluster 3.0 5/02 software release. (If you want to integrate any file system locally into a Sun Cluster configured for failover, you must upgrade to Sun Cluster 3.0 5/02 and use the HAStoragePlus resource type. See "Planning the Cluster File System Configuration" in the Sun Cluster 3.0 12/01 Data Services Installation and Configuration Guide for more information.)

• In cases where a data service resource group has a node list in which some of the nodes are not directly connected to the storage, you must configure HAStorage or HAStoragePlus resources in the resource group and set the dependency of the other data service resources to the HAStorage or HAStoragePlus resource. This requirement coordinates the boot order between the storage and the data services.

• If your data service is disk intensive, such as Sun Cluster HA for Oracle and Sun Cluster HA for NFS, ensure that you perform the following tasks.

  • Add a HAStorage or HAStoragePlus resource to your data service resource group.

  • Switch the HAStorage or HAStoragePlus resource online.

  • Set the dependency of your data service resources to the HAStorage or HAStoragePlus resource.

  • Set AffinityOn to True.

    When you perform these tasks, the resource groups and disk device groups are collocated on the same node.

• If your data service is not disk intensive-such as one that reads all of its files at startup (for example, Sun Cluster HA for DNS)-configuring the HAStorage or HAStoragePlus resource type is optional.

See the individual chapters on data services in this book for specific recommendations.

See "Synchronizing the Startups Between Resource Groups and Disk Device Groups" for information about the relationship between disk device groups and resource groups. The SUNW.HAStorage(5) and SUNW.HAStoragePlus(5) man pages provides additional details.

See "Enabling Highly Available Local File Systems" for procedures for mounting of file systems such as VxFS in a local mode. The SUNW.HAStoragePlus man page provides additional details.