Technical data

Figure 1–2: Generic Two-Node Cluster with Minimum Disk Configuration
and 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
Quorum
Tru64
UNIX
Disk
Member 1
root (/)
swap
ZK-1588U-AI
1.5 Growing a Cluster from Minimum Storage to an 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:
• The starting point is a cluster with minimum storage for highly available
applications (Section 1.5.1).
• By adding a second storage shelf, you have a cluster with more storage
for applications, but the single SCSI bus is a single point of failure
(Section 1.5.2).
• Adding a second SCSI bus allows the use of LSM to mirror the
clusterwide root (/), /usr, and /var file systems, the member system
swap disks, and the data disks. However, because LSM cannot mirror the
member system boot or quorum disks, full redundancy is not achieved
(Section 1.5.3).
Introduction 1–7