Administration manual for a discussion of how and when to use a quorum disk.

Figure 1–2: Generic Two-Node Cluster with Minimum Disk Configuration and Quorum Disk

Network

Member

System

1

PCI SCSI

Adapter

Memory Channel

Tru64

UNIX

Disk

Member

System

2

PCI SCSI

Adapter

Shared SCSI Bus

Cluster File

Member 1

Member 1

Quorum

System

 

 

root (/)

root (/)

root (/)

 

/usr

 

swap

swap

 

/var

 

 

 

 

ZK-1588U-AI

1.6Growing a Cluster from Minimum Storage to a NSPOF Cluster

The following sections take a progression of clusters from a cluster with minimum storage to a no-single-point-of-failure (NSPOF) cluster; a cluster where one hardware failure will not interrupt the cluster operation:

A cluster with minimum storage for highly available applications (Section 1.6.1).

A cluster with more storage, but the single SCSI bus is a single point of failure (Section 1.6.2).

Adding a second SCSI bus allows the use of LSM to mirror the /usr and /var file systems and data disks. However, as LSM cannot mirror the root (/), member system boot, swap, or quorum disks, so full redundancy is not achieved (Section 1.6.3).

Introduction 1–7

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Compaq AA-RHGWB-TE manual Growing a Cluster from Minimum Storage to a Nspof Cluster