Compaq AA-RHGWB-TE - Manual (Page 28)

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.
Figure 1–1: Two-Node Cluster with Minimum Disk Configuration and No
Quorum Disk
Member
System
1
Network
Memory Channel
Shared SCSI Bus
PCI SCSI
Adapter
Member
System
2
PCI SCSI
Adapter
Cluster File
System
root (/)
/usr
/var
Member 1
root (/)
swap
Member 2
root (/)
swap
Tru64
UNIX
Disk
ZK-1587U-AI
Figure 1–2 shows the same generic two-node cluster as shown in Figure 1–1,
but with the addition of a quorum disk. By adding a quorum disk, a cluster
may be formed if both systems are operational, or if either of the systems
and the quorum disk is operational. This cluster has a higher availability
than the cluster shown in Figure 1–1. See the TruCluster Server Cluster
1–6 Introduction