Understanding HAStoragePlus

The HAStoragePlus resource type can be used to configure the following options.

• Coordinate the boot order of disk devices and resource groups. Other resources in the resource group that contains the HAStoragePlus resource are brought online only after the disk device resources become available.

• With AffinityOn set to True, enforce collocation of resource groups and device groups on the same node. This enforced collocation enhances the performance of disk-intensive data services.

In addition, HAStoragePlus is capable of mounting local and global file systems. For more information, see Planning the Cluster File System Configuration.

If the device group is switched to another node while the HAStoragePlus resource is online, AffinityOn has no effect. The resource group does not migrate with the device group. However, if the resource group is switched to another node, the setting of AffinityOn to True causes the device group to follow the resource group to the new node.

See Synchronizing the Startups Between Resource Groups and Device Groups for information about the relationship between device groups and resource groups.

See Enabling Highly Available Local File Systems for procedures for mounting of file systems such as VxFS and Solaris ZFS (Zettabyte File System) in a local mode. The SUNW.HAStoragePlus(5) man page provides additional details.

Determining Whether Your Data Service Requires HAStoragePlus

The following types of data services require HAStoragePlus:

• Data services with nodes that are not directly connected to storage

• Data services that are disk intensive

Data Services With Nodes That Are Not Directly Connected to Storage

Some nodes in the node list of a data service's resource group might not be directly connected to the storage. In this situation, you must coordinate the boot order between the storage and the data service. To meet this requirement, configure the resource group as follows:

• Configure HAStoragePlus resources in the resource group.

• Set the dependency of the other data service resources to the HAStoragePlus resource.

Data Services That Are Disk Intensive

Some data services, such as Sun Cluster HA for Oracle and Sun Cluster HA for NFS are disk intensive. If your data service is disk intensive, ensure that the resource groups and device groups are collocated on the same node. To meet this requirement, perform the following tasks.

• Adding an HAStoragePlus resource to your data service resource group

• Switching the HAStoragePlus resource online

• Setting the dependency of your data service resources to the HAStoragePlus resource

• Setting AffinityOn to True

The failback settings must be identical for both the resource group and device groups.

Some data services are not disk intensive. For example, Sun Cluster HA for DNS, which reads all of its files at startup, is not disk intensive. If your data service is not disk intensive, configuring the HAStoragePlus resource type is optional.