Changing the shared file system quorum type

The shared file system quorum type is assigned automatically during the setup of the IBM® Db2® pureScale® Feature. Because the quorum type selected is based upon the number of hosts in the cluster, you must change the quorum type after adding or removing hosts from the Db2 instance.

Before you begin

If you are changing to a disk tiebreaker, the disk you specify must be of the device path format (for example: /dev/hdisk2) and it must be accessible on all of the nodes. Unlike the disk tiebreaker for the cluster manager, this disk can be reused in a shared file system, or in a disk on an already defined file system.
To perform this task, you must be the Db2 cluster servicesadministrator.

About this task

There are two quorum types for Storage Scale:

Disk tiebreaker: a shared disk that determines which surviving group of hosts in the Storage Scale cluster has operational quorum
Majority node set: the surviving group of hosts in the Storage Scale with the majority has operational quorum

The quorum type is automatically chosen by the Db2 installer based upon the rule in Table 1.

Table 1. The relationship between number of hosts in a Storage Scale cluster and the quorum type
Total amount of hosts in Storage Scale cluster	Storage Scale quorum type
Equal or less than 8	Disk tiebreaker
More than 8	Majority Node Set

When the number of hosts in the Storage Scale increases from eight hosts or decreases from nine hosts, an error message is returned indicating that the quorum type must be changed.

Procedure

To change the quorum type to a disk tiebreaker, issue this command:
```
db2cluster -cfs -set -tiebreaker -disk diskname
```
To change the quorum type to a majority node set, issue this command:
```
db2cluster -cfs -set -tiebreaker -majority
```