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Chapter 5. Replacing components
The DS4500 Storage Subsystem contains two RAID controllers, a cooling system
that contain four fans (the storage subsystem fan and the fan and communications
module), mini hubs, SFP modules, and a power system. This chapter includes
detailed instructions on how to replace these components.
Attention: Always replace a failed component as soon as possible. The Recovery
Guru menu function in the DS4500 Storage Subsystem identifies failed
components.
When performing replacement procedures for each component, take precautions to
avoid damage from static electricity. For details about handling static-sensitive
devices, see “Handling static-sensitive devices” on page 24.
Replacing a controller
Attention: Before you replace a controller, consider the following factors:
v You can hot swap or replace a failed controller while the DS4500 Storage
Subsystem is in operation as long as the host has a Fibre Channel connection to
the functioning controller and is in a “passive” or “offline” status in the
storage-management software.
v If cache mirroring is enabled in redundant controllers and one controller fails, the
second controller assumes processing functions without data loss. However,
some or all data might be lost if cache mirroring is disabled and a failure occurs
before data is written from cache memory to disk.
v Removing a controller that is operating normally (not failed) can result in data
loss. Only remove a controller that:
– has a fault LED that is lit, indicating that it has failed (see “Controller LEDs”
on page 128)
– Is marked as “Failed” (offline) through the storage-management software
v
The two controllers are automatically synchronized when you replace a failed
controller. The storage-management software automatically synchronizes the
firmware between the existing controller and the new controller.
v If you are replacing an optimal controller, first make sure that the other controller
is optimal and that the fibre channel path from the hosts to the other controller is
also optimal.
v If you replace the controller CRU and still experience problems, the DS4500
Storage Subsystem might have other defective components or connections.
Check the storage-management software for indications of other component
failures.
When
instructed by the storage-management software, replace a controller CRU by
using the following procedure:
Attention: After replacing a controller, always use the storage-management
software to verify the firmware levels.
1. Remove the DS4500 bezel (see “Removing the front bezel” on page 32).
2. Remove the failed controller, as shown in Figure 98 on page 146.
a. Using your thumbs, squeeze the two center tabs and pull both controller
handles outward with your fingers.
© Copyright IBM Corp. 2006 145