Use the chquorum command to change the quorum
association.
Syntax
chquorum [ -active ] [ { -mdisk { mdisk_id | mdisk_name } | -drivedrive_id } ] [ -overrideyes|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. To change the active IP quorum application, the quorum application must
be restarted. The quorum application that connects first is chosen and is active (if
valid).
The chquorum command is not
synchronous, but usually takes only a few seconds to complete. In some situations it can take
several minutes.
The 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.
Number of extents reserved by extent size
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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