Technical data

file system cannot also be used as the member boot disk or as the quorum
disk.
1.3.1.3 Member Boot Disk
Each member has a boot disk. A boot disk contains that member’s boot,
swap, and cluster-status partitions. For example, dsk1 is the boot disk for
the first member and dsk2 is the boot disk for the second member:
dsk1 first member’s boot disk [pepicelli]
dsk2 second member’s boot disk [polishham]
The installation scripts reformat each member’s boot disk to contain three
partitions: an a partition for that member’s root (/) file system, a b partition
for swap, and an h partition for cluster status information. (There are no
/usr or /var file systems on a member’s boot 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
Cluster
Administration manual for more information.
1.3.1.4 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 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.
1–4 Introduction