IBM System Storage DS3000, Руководство по программированию

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Setting the Controller Operational Mode
A controller has three operational modes:
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Online
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Offline
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Service
Placing a controller online sets it to the Optimal state and makes it active and available for I/O
operations. Placing a controller offline makes it unavailable for I/O operations and moves its subsystems
to the other controller if failover protection is enabled.
Taking a controller offline can seriously impact data integrity and storage subsystem operation.
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If you do not use write cache mirroring, data in the cache of the controller you place offline is lost.
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If you take a controller offline and you have controller failover protection through a host multi-path
driver, the other controller in the pair takes over. subsystems and their associated logical drives that
were assigned to the offline controller are automatically reassigned to the remaining controller. If you
do not have a multi-path driver installed on the application host and you take a controller offline while
the application is using associated logical drives, application errors will occur.
Attention: Possible loss of data access – Placing a controller offline can cause loss of data.
Use Service mode to replace CRUs, such as a controller. Placing a controller in Service mode makes it
unavailable for I/O operations and moves its subsystems to the second controller without affecting the
preferred path of the subsystem. This action might significantly reduce performance. The subsystems are
automatically transferred back to the preferred controller when it is placed back online.
If you change a controller to Service mode while an application is using the associated logical drives on
the controller, the change causes I/O errors unless a multi-path driver is installed on the host. Before you
place a controller in Service mode, make sure that the logical drives are not in use, or a multi-path driver
is installed on all of the hosts that are using these logical drives.
In addition, if you do not have a multi-path driver, you must make appropriate operating system-specific
modifications to make sure that the subsystems moved are accessed on the new path when you change to
Service mode.
Important: Place a controller in Service mode only under the direction of an IBM Technical Support
representative.
To change the operational mode of a controller, use this command:
set controller [(a | b)] availability=(online | offline | serviceMode)
Changing the Controller Ownership
You can change which controller is the owner of a logical drive by using the
set logical drive
command. The command takes this form:
set(allLogicalDrives|logicalDrive [ logicalDriveName ]|logicalDrives
[ logicalDriveName1...logicalDriveNameN ]
|logicalDrive < wwID >)owner=(a|b)
Initializing a Drive
Attention: Possible loss of data access – When you initialize a disk drive, all data on the disk drive is
lost.
You must initialize a disk drive when you have moved a disk drive that was previously part of a
multidisk subsystem from one storage subsystem to another. If you do not move the entire set of disk
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IBM System Storage DS3000, DS4000, and DS5000: Command Line Interface and Script Commands Programming Guide