Use the chquorum command to change the
quorum association.
Syntax
chquorum [ -active ] [ { -mdisk { mdisk_id | mdisk_name } | -drive drive_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. 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 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.
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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