Compaq AA-RHGWB-TE manual Generic Two-Node Cluster, Quorum Disk

A member boot disk cannot contain one of the clusterwide root (/), /usr, and /var file systems. Also, a member boot disk cannot be used as the quorum disk. A member disk can contain more than the three required partitions. You can move the swap partition off the member boot disk. See the TruCluster Server Cluster Administration manual for more information.

1.4.1.4 Quorum Disk

The quorum disk allows greater availability for clusters consisting of two members. Its h partition contains cluster status and quorum information. See the TruCluster Server Cluster Administration manual for a discussion of how and when to use a quorum disk.

The following restrictions apply to the use of a quorum disk:

•A cluster can have only one quorum disk.

•The quorum disk should be on a shared bus to which all cluster members are directly connected. If it is not, members that do not have a direct connection to the quorum disk may lose quorum before members that do have a direct connection to it.

•The quorum disk must not contain any data. The clu_quorum command will overwrite existing data when initializing the quorum disk. The integrity of data (or file system metadata) placed on the quorum disk from a running cluster is not guaranteed across member failures.

This means that the member boot disks and the disk holding the clusterwide root (/) cannot be used as quorum disks.

•The quorum disk can be small. The cluster subsystems use only 1 MB of the disk.

•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 second point of failure).

•You cannot use the Logical Storage Manager (LSM) on the quorum disk.

1.5Generic Two-Node Cluster

This section describes a generic two-node cluster with the minimum disk layout of four disks. Note that additional disks may be needed for highly available applications. In this section, and the following sections, the type of PCI SCSI bus adapter is not significant. Also, although an important consideration, SCSI bus cabling, including Y cables or trilink connectors, termination, and the use of UltraSCSI hubs is not considered at this time.

Introduction 1–5