Solaris Cluster Configuration/Setup/Guideline for 3rd Mediator Host in Campus Cluster (Doc ID 1615755.1)

Last updated on MARCH 03, 2022

Applies to:

Goal

One of the new features in Solaris Cluster 3.2 11/09 update3 and higher is the Solaris Volume Manager Three-Mediator support.

Quote from the release notes :

Solaris Cluster software now supports mediators for three-room campus cluster configurations that use Solaris Volume Manager or multi-owner Solaris Volume Manager for Solaris Cluster. A two-room (two-node) campus cluster now works with a third mediator host outside the cluster. The third mediator host does not have to be attached to the shared storage that contains the disk set for which the host is a mediator.
The mediator host uses Solaris Volume Manager to facilitate automatic recovery for a two-room campus cluster by tracking which mirrored half of the storage is the most up to date. The third mediator then provides mediator quorum to allow Solaris Volume Manager to recover from a destroyed room.

There are some more details in the Sun Cluster 3.2 11/09 Release Notes in the section Changes to Guidelines for Mediators

Some more helpful documents around the design are:
- Oracle Solaris Cluster 4.1 Hardware Administration Manual - Campus Clustering With Oracle Solaris Cluster Software
- Oracle Solaris Cluster Software Installation Guide - Configuring Dual-String Mediators

In summary...
Advantages:

• The 3rd mediator host is used to get the majority of Solaris Volume Manager configuration when one room is lost due to an error.
• The 3rd mediator host only need public network connection. (Must not be part of the cluster and need no connection to the shared storage).

Consider:

• One more room necessary
• One more host for administration, but if using a Solaris Cluster quorum server then the 3rd mediator can be on the same host.

Solution

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