If The Enclosure Does Not Initialize; Host I/O; Dealing With Hardware Faults - Seagate Exos AP 4U100 Installation And Maintenance Manual

Determine where the fault is occurring
When a fault occurs, the Module Fault LED—located in the lower left corner of the enclosure front panel—illuminates. See
"Overview of front panel LEDs" (page
back and top (must remove a lid) of the enclosure to narrow the fault to a CRU, connection, or both.
• See "Overview of rear panel LEDs" (page 33)
• See "Overview of top LEDs" (page 38)
The LEDs help you identify the location of a CRU reporting a fault.
Isolate the fault
Occasionally, it might become necessary to isolate a fault. This is particularly true with data paths, due to the number of
components comprising the data path. For example, if a host-side data error occurs, it could be caused by any of the
components in the data path: controller module, cable, or data host. By isolating the fault to one of the components
within the storage system, you will be able to determine the necessary corrective action more quickly.

If the enclosure does not initialize

It may take up to two minutes for all enclosures to initialize. If an enclosure does not initialize:
• Power cycle the system
• Make sure the power cord is properly connected, and check the power source to which it is connected
• Check log for errors

Host I/O

When troubleshooting drive and connectivity faults, stop I/O to the affected drive groups from all hosts as a data
protection precaution. As an additional data protection precaution, it is helpful to conduct regularly scheduled backups of
your data. See

Dealing with hardware faults

Ensure that you have obtained a replacement module of the same type before removing any faulty module as described
in "Module removal and replacement" (page
IMPORTANT: If the enclosure system is powered up and you remove any module, replace it immediately. If the system
is used with any modules missing for more than a few seconds, the enclosure(s) can overheat, causing power failure and
potential data loss. Such action can invalidate the product warranty.
IMPORTANT: Observe applicable/conventional ESD precautions when handling modules and components, as
described in "ESD precautions" (page
exposed circuitry.
86 Troubleshooting and problem solving
32). Check the status of the other front panel LEDs. Also check the LEDs on the
"Stopping I/O" (page 107).
89). Avoid contact with midplane components, module connectors, leads, pins, and
89).