Glossary

Cluster Interconnect

The hardware networking infrastructure that includes cables, cluster transport junctions, and cluster transport adapters. The Sun Cluster and data service software use this infrastructure for intra-cluster communication.

Cluster Member

An active member of the current cluster incarnation. This member is capable of sharing resources with other cluster members and providing services both to other cluster members and to clients of the cluster.

Co-Location

The property of being on the same node. Specific to Remote Mirror software, for a configured replica, the logical hostname and the associated device group are collocated on the same node, along with any other failover data services or highly available applications. For Point-in-Time Copy software, co-location refers to the device group and other software failover data services or highly available applications.

Data service

Highly Available (HA) applications within the Sun Cluster environment are also known as data services. The term data service is used to describe a third-party application that has been configured to run on a cluster rather than on a single server. A data service includes the application software and Sun Cluster software that starts, stops, and monitors the application.

Device group

A user-defined group of device resources, such as disks, that can be mastered from different nodes in a cluster HA configuration. This group can include device resources of disks, Solaris Volume Manager disksets, VERITAS Volume Manager disk groups, Remote Mirror volumes or Point-in-Time Copy sets, or any combination thereof.

DID name

Used to identify global devices in a Sun Cluster system. It is a clustering identifier with a one-to-one or a one-to-many relationship with Solaris logical names. It takes the form dXsY, where X is an integer and Y is the slice name. See also Solaris logical name.

Exportable Shadow

A Point-in-Time Copy Set's shadow volume in a Sun Cluster OE, that is in a different device group than the set's master and bitmap volumes. The ability to create a set with this configuration is available only when using the iiadm -n option, when initially creating the Point-in-Time Volume set.

Failover

The automatic relocation of a resource group or a device group from a current primary node to a new primary node after a failure has occurred.

Failover resource

A resource, each of whose resources can correctly be mastered by only one node at a time.

Global device

A namespace that contains the logical, cluster-wide names for global devices. Local devices in the Solaris environment are defined in the /dev/dsk/c?t?d?s? and /dev/rdsk/c?t?d?s? device directories. For each local device accessible on any cluster node, there is a derived disk device name based on the unique DID name of the underlying physical device. For each unique DID named deviced /dev/did/dsk/d<n> and /dev/did/rdsk/d<n>, there is a corresponding /dev/global/dsk/d<n> and /dev/global/rdsk/d<n> name.

Multihost disk

A disk that is physically connected to multiple nodes.

Network resource

A resource that contains one or more logical hostnames or shared addresses.

Point-in-Time Copy

Using the Availability Suite command iiadm, one configures a master, shadow and bitmap volume as a Point-in-Time Copy set. A Point-in-Time Copy can be further configured, such that it is a highly available resource in a Sun Cluster OE.

Potential primary

A cluster member that is able to master a failover resource type if the primary node fails.

Primary

A node on which a resource group or device group is currently online. That is, a primary is a node that is currently hosting or implementing the service associated with the resource. See also Secondary,

Primary and secondary hosts and nodes

In this guide and the Remote Mirror software documentation, the terms primary host and secondary host are used as follows.

The primary and secondary hosts are physically-separate servers running the Remote Mirror software. The primary host contains the primary volume and bitmap volume to be initially replicated to a remote server called a secondary host. The secondary hosts contains the secondary volume and bitmap volume

The terms primary node and secondary node refer to the Sun Cluster logical hostname that represents the current node that is also master the device group associated with the Remote Mirror set.

Resource

An instance of a resource type. Many resources of the same type might exist, each resource having its own name and set of property values, so that many instances of the underlying application might run on the cluster.

Resource group

A collection of resources that are managed by the RGM as a unit. Each resource that is to be managed by the RGM must be configured in a resource group. Typically, related and interdependent resources are grouped.

Resource type

The unique name given to a data service or LogicalHostname cluster object. Data service resource types can either be failover types or scalable types, although the Availability Suite software is only a failover data service.

Rolling upgrade

In a Sun Cluster configuration, an upgrade that is performed sequentially on one cluster node at a time. During a rolling upgrade, the cluster remains in production and services continue to run on the other nodes.

Secondary

A cluster member that is available to master disk device groups and resource groups in the event that the primary fails. See also Primary.

Solaris logical name

The names typically used to manage Solaris devices. For disks, these usually look something like /dev/rdsk/c0t2d0s2. For each one of these Solaris logical device names, there is an underlying Solaris physical device name. See also DID name.

Solaris Volume Manager

A software product that provides data reliability through disk striping, concatenation, mirroring, and dynamic growth of metadevices or volumes.

Switchover

The orderly transfer of a resource group or device group from one master (node) in a cluster to another master (or multiple masters, if resource groups are configured for multiple primaries). A switchover is initiated by an administrator by using the scswitch(1M) command.

VERITAS Volume Manager (VxVM)

A software product that provides data reliability through disk striping, concatenation, mirroring, and dynamic growth of metadevices or volumes.