C H A P T E R 6

SunCluster

This chapter describes SunCluster troubleshooting issues.

The following topics are included:

Point-in-Time Copy

Remote Mirror

Point-in-Time Copy and Remote Mirror Interoperability

Point-in-Time Copy

The Availability Suite product set is supported as a Highly Available Data Service in a Sun Cluster Operating Environment (OE). Since each unique instance of an Availability Suite configured data service, Point-in-Time Copy Set, or Remote Mirror set is active on one node of the Sun Cluster and inactive on all others, there is no limit to the number of Sun Cluster nodes in which Availability Suite volumes can be configured.

Through the configuration of SUNW.HAStoragePlus for Point-in-Time Copy volumes or the configuration of SUNW.HAStoragePlus and SUNW.LogicalHostname for Remote Mirror volumes, Sun Cluster resource groups can be configured with Availability Suite, Solaris Volume Manager, and a vast array of highly available applications to provided Highly-Available, failover data services.

The volumes of a Point-in-Time Copy Set or Remote Mirror Volume set can be raw global devices, named global devices, Solaris Volume Manager volumes, or VxVM volumes. A named global device is a special reconfiguration of two or more global devices under a system administrator specified device name.

Configuration

Point-in-Time Copy in a Sun Cluster operating environment differs from a Solaris operating system in that all constituate volumes in an single set must be created out of the same device group, with the exception of Export/Import/Join support. This requirement is due to the fact that in a Sun Cluster, only a single device group is switched between configured Sun Cluster nodes at the same time. Thus, when a set is disabled on one node and resumed on another node, the master, shadow, bitmap, and optional overflow volume must switch as a collection of 3 or 4 volumes.

Export/Import/Join

Within a Sun Cluster operating environment there exists the ability to configure an exportable shadow volume, a shadow volume that is not in the same device group as the other constituate volumes in an single set. This permits the use of the Export, Import, and Join command in a Sun Cluster operating environment, allowing the shadow volume to be deported from the current node in the Sun Cluster.

Due to current restrictions in a Sun Cluster OE, a volume in a device group under the control of Sun Cluster software, cannot be moved to a node outside of the Sun Cluster, limiting E/I/J support to nodes within the current Sun Cluster.

Remote Mirror

Remote Mirror in a Sun Cluster operating environment differs from in a Solaris operating system, in that all constituate volumes in an single set must be created out of the same device group. This requirement is due to the fact that in a Sun Cluster, only a single device group is switched between configured Sun Cluster nodes at the same time. Thus when a set is disabled on one node and resumed on another node, the primary or secondary volume, bitmap and optional disk queue must switch as a collection of 2 or 3 volumes.

Point-in-Time Copy and Remote Mirror Interoperability

A Remote Mirror set is the combination of a primary and secondary hostname along with a primary and secondary volume and bitmap pair. The primary or secondary nodes can be either Sun Cluster or Solaris nodes.

A Remote Mirror set in a Sun Cluster operating environment differs from one in a Solaris operating environment through the use of a global device or volume bound to "named" device group and "named" logical hostname, both of which are resource types, configured in a single resource group, that can switchover between configured nodes under Sun Cluster control.

A "named" Sun Cluster resource group must be created, containing at a minimum one SUNW.HAStoragePlus and one SUNW.LogicalHostname resource type. The "name" of the resource group is based on the "name" of the device group configured under SUNW.HAStoragePlus. For example, if the device group name is production, as in /dev/md/production/rdsk/d100, the resource group name might be production-stor-rg.