Chapter 2

Key Concepts - Hardware Service Providers

This chapter describes the key concepts related to the hardware components of a SunPlex system configuration. The topics covered include:

The SunPlex System Hardware Components

This information is directed primarily toward hardware service providers. These concepts can help service providers understand the relationships between the hardware components before they install, configure, or service cluster hardware. Cluster system administrators might also find this information useful as background to installing, configuring, and administering cluster software.

A cluster is composed of several hardware components including:

Cluster nodes with local disks (unshared)
Multihost storage (disks shared between nodes)
Removable media (tapes and CD-ROM)
Cluster interconnect
Public network interfaces
Client systems
Administrative console
Console access devices

The SunPlex system enables you to combine these components into a variety of configurations, described in Sun Cluster Topology Examples.

The following figure shows a sample cluster configuration.

Figure 2-1 Sample Two-Node Cluster Configuration

Illustration's purpose is to show a 2-node cluster with public/private networks, interconnect hardware, local/multihost disks, console, and clients.

Cluster Nodes

A cluster node is a machine running both the Solaris operating environment and Sun Cluster software, and is either a current member of the cluster (a cluster member), or a potential member. The Sun Cluster software enables you to have from two to eight nodes in a cluster. See Sun Cluster Topology Examples for the supported node configurations.

Cluster nodes are generally attached to one or more multihost disks. Nodes not attached to multihost disks use the cluster file system to access the multihost disks. For example, one scalable services configuration allows nodes to service requests without being directly attached to multihost disks.

In addition, nodes in parallel database configurations share concurrent access to all the disks. See Multihost Disks and Chapter 3, Key Concepts - Administration and Application Development for more information on parallel database configurations.

All nodes in the cluster are grouped under a common name--the cluster name--which is used for accessing and managing the cluster.

Public network adapters attach nodes to the public networks, providing client access to the cluster.

Cluster members communicate with the other nodes in the cluster through one or more physically independent networks. This set of physically independent networks is referred to as the cluster interconnect.

Every node in the cluster is aware when another node joins or leaves the cluster. Additionally, every node in the cluster is aware of the resources that are running locally as well as the resources that are running on the other cluster nodes.

Nodes in the same cluster should have similar processing, memory, and I/O capability to enable failover to occur without significant degradation in performance. Because of the possibility of failover, every node must have enough excess capacity to take on the workload of all nodes for which they are a backup or secondary.

Each node boots its own individual root (/) file system.

Software Components for Cluster Hardware Members

To function as a cluster member, the following software must be installed:

Solaris operating environment
Sun Cluster software
Data service application
Volume management (Solaris Volume Manager™ or VERITAS Volume Manager)

An exception is a configuration that uses hardware redundant array of independent disks (RAID). This configuration may not require a software volume manager such as Solaris Volume Manager or VERITAS Volume Manager.

See the Sun Cluster 3.1 Software Installation Guide for information on how to install the Solaris operating environment, Sun Cluster, and volume management software.

See the Sun Cluster 3.1 Data Services Installation and Configuration Guide for information on how to install and configure data services.

See Chapter 3, Key Concepts - Administration and Application Development for conceptual information on the preceding software components.

The following figure provides a high-level view of the software components that work together to create the Sun Cluster software environment.

Figure 2-2 High-Level Relationship of Sun Cluster Software Components

Illustration: The preceding context describes the graphic.

See Chapter 4, Frequently Asked Questions for questions and answers about cluster members.


	Chapter 2 Key Concepts - Hardware Service Providers This chapter describes the key concepts related to the hardware components of a SunPlex system configuration. The topics covered include: Cluster Nodes Multihost Disks Local Disks Removable Media Cluster Interconnect Public Network Interfaces Client Systems Console Access Devices Administrative Console Sun Cluster Topology Examples The SunPlex System Hardware Components This information is directed primarily toward hardware service providers. These concepts can help service providers understand the relationships between the hardware components before they install, configure, or service cluster hardware. Cluster system administrators might also find this information useful as background to installing, configuring, and administering cluster software. A cluster is composed of several hardware components including: Cluster nodes with local disks (unshared) Multihost storage (disks shared between nodes) Removable media (tapes and CD-ROM) Cluster interconnect Public network interfaces Client systems Administrative console Console access devices The SunPlex system enables you to combine these components into a variety of configurations, described in Sun Cluster Topology Examples. The following figure shows a sample cluster configuration. Figure 2-1 Sample Two-Node Cluster Configuration Cluster Nodes A cluster node is a machine running both the Solaris operating environment and Sun Cluster software, and is either a current member of the cluster (a cluster member), or a potential member. The Sun Cluster software enables you to have from two to eight nodes in a cluster. See Sun Cluster Topology Examples for the supported node configurations. Cluster nodes are generally attached to one or more multihost disks. Nodes not attached to multihost disks use the cluster file system to access the multihost disks. For example, one scalable services configuration allows nodes to service requests without being directly attached to multihost disks. In addition, nodes in parallel database configurations share concurrent access to all the disks. See Multihost Disks and Chapter 3, Key Concepts - Administration and Application Development for more information on parallel database configurations. All nodes in the cluster are grouped under a common name--the cluster name--which is used for accessing and managing the cluster. Public network adapters attach nodes to the public networks, providing client access to the cluster. Cluster members communicate with the other nodes in the cluster through one or more physically independent networks. This set of physically independent networks is referred to as the cluster interconnect. Every node in the cluster is aware when another node joins or leaves the cluster. Additionally, every node in the cluster is aware of the resources that are running locally as well as the resources that are running on the other cluster nodes. Nodes in the same cluster should have similar processing, memory, and I/O capability to enable failover to occur without significant degradation in performance. Because of the possibility of failover, every node must have enough excess capacity to take on the workload of all nodes for which they are a backup or secondary. Each node boots its own individual root (`/`) file system. Software Components for Cluster Hardware Members To function as a cluster member, the following software must be installed: Solaris operating environment Sun Cluster software Data service application Volume management (Solaris Volume Manager™ or VERITAS Volume Manager) An exception is a configuration that uses hardware redundant array of independent disks (RAID). This configuration may not require a software volume manager such as Solaris Volume Manager or VERITAS Volume Manager. See the Sun Cluster 3.1 Software Installation Guide for information on how to install the Solaris operating environment, Sun Cluster, and volume management software. See the Sun Cluster 3.1 Data Services Installation and Configuration Guide for information on how to install and configure data services. See Chapter 3, Key Concepts - Administration and Application Development for conceptual information on the preceding software components. The following figure provides a high-level view of the software components that work together to create the Sun Cluster software environment. Figure 2-2 High-Level Relationship of Sun Cluster Software Components See Chapter 4, Frequently Asked Questions for questions and answers about cluster members.