Quorum disk

A quorum disk is an MDisk or a managed drive that contains a reserved area that is used exclusively for system management.

A system uses a quorum disk for two purposes:

To break a tie when a SAN fault occurs, when exactly half of the nodes that were previously a member of the system are present.
To hold a copy of important system configuration data. Just over 256 MB is reserved for this purpose on each quorum disk candidate.

Quorum disk configuration
A quorum disk is an MDisk or a managed drive that contains a reserved area that is used exclusively for system management. A system automatically assigns quorum disk candidates. When you add new storage to a system or remove existing storage, however, it is a good practice to review the quorum disk assignments.
IP quorum configuration
The IP quorum application is a Java™ application that runs on a separate server or host. An IP quorum application is used in Ethernet networks to resolve failure scenarios where half the nodes or enclosures on the system become unavailable. In this scenario, the application determines which nodes or enclosures can continue processing host operations and avoids a split system, where both halves of the system continue to process I/O independently. In addition, an IP quorum application also provides a quorum disk that stores configuration metadata that is used for system recovery. For systems that already have a quorum disk configured for metadata recovery, you can configure the IP quorum application to provide only tie-break operations.
Manual quorum disk override in a HyperSwap system
A manual quorum disk override is required when you experience a rolling disaster. In rare situations, the system is subject to what is referred to as a rolling disaster. A rolling disaster occurs when an incident has wide scope, and its effects are felt in multiple steps over an extended time period. The following example scenario describes a rolling disaster and shows how to recover from that rolling disaster.

Parent topic: Configuration details