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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