chquorum

Use the chquorum command to change the quorum association.

Syntax

chquorum [ -active ] [ { -mdisk { mdisk_id | mdisk_name } | -drivedrive_id } ] [ -override yes|no ] quorum_id

Parameters

-active
(Optional) Makes the specified quorum ID the active one. The active parameter must be used if neither the mdisk nor the drive parameters are specified.
-mdiskmdisk_id | mdisk_name | -drivedrive_id
(Optional) Specifies the MDisk or drive to be this quorum ID.
-override yes|no
Enables the automatic quorum selection to be overridden. In this state, the quorum disk is only moved if the resources are offline. Do not use this parameter unless a specific quorum disk is required for the configuration.
quorum_id
(Required) Specifies which quorum ID to change. Permitted values are values are 0, 1, and 2.

Description

Use the chquorum command to change the quorum association. To identify the drive or MDisk that is the current active quorum disk, use the lsquorum command.
Remember: You cannot use this command to change the active quorum device when you use an IP quorum application.

The chquorum command is not synchronous, but usually takes only a few seconds to complete. In some situations it can take several minutes.

The clustered system (system) uses the quorum disk or drive as a tie breaker when exactly half of the nodes that were previously a member of the system are present.

Attention: Only assign quorum disks to drives in the control enclosure or to external MDisks. Some maintenance procedures require that quorum is moved temporarily to expansion enclosures. Once that procedure is complete, return the quorum drives to the control enclosure.

The use of a quorum disk or drive allows the system to manage a SAN fault that splits the system exactly in half. One half of the system continues to operate and the other half stops until SAN connectivity is restored.

There is only one quorum disk or drive; however, the system uses three as quorum candidates. The system selects the actual quorum disk or drive from the pool of quorum candidates. The quorum candidates also hold a copy of important system metadata. Just over 256 MB is reserved for this purpose on each quorum candidate disk. When using an MDisk as quorum disk, this space is allocated from the storage pool.

The number of extents required depends on the extent size for the storage pool containing the MDisk. Table 1 provides the number of extents reserved for quorum use by extent size.
Table 1. Number of extents reserved by extent size
Extent size (MB) Number of extents reserved for quorum use
16 17
32 9
64 5
128 3
256 2
512 1
1024 1
2048 1
4096 1
8192 1

When you issue this command, the MDisk or drive that currently is assigned the quorum index number is set to a nonquorum disk. The system automatically assigns quorum indexes.

You can set the active quorum disk or drive with the -active parameter. This can be useful in a system configuration to ensure that the most highly-available quorum disk or drive is used.

Note: Quorum disks must be allocated one per site when the system topology is hyperswap.

An invocation example

chquorum -mdisk 45 2

The resulting output:

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