Technical data

• A quorum disk can have either 1 vote or no votes. In general, a quorum
disk should always be assigned a vote. You might assign an existing
quorum disk no votes in certain testing or transitory configurations,
such as a one-member cluster (in which a voting quorum disk introduces
a single point of failure).
• You cannot use the Logical Storage Manager (LSM) on the quorum disk.
1.4 Generic Two-Node Cluster
This section describes a generic two-node cluster with the minimum disk
layout of four disks. Additional disks may be needed for highly available
applications. In this section, and the following sections, the type of
peripheral component interconnect (PCI) SCSI bus adapter is not significant.
Also, although an important consideration, SCSI bus cabling, including Y
cables or trilink connectors, termination, the use of UltraSCSI hubs, and the
use of Fibre Channel are not considered at this time.
Figure 1–1 shows a generic two-node cluster with the minimum number
of disks.
• Tru64 UNIX disk
• Clusterwide root (/), /usr, and /var
• Member 1 boot disk
• Member 2 boot disk
A minimum configuration cluster may have reduced availability due to the
lack of a quorum disk. As shown, with only two-member systems, both
systems must be operational to achieve quorum and form a cluster. If only
one system is operational, it will loop, waiting for the second system to boot
before a cluster can be formed. If one system crashes, you lose the cluster.
Introduction 1–5