1.If you have time, stop all I/O activity to the storage subsystem by shutting down the host or disconnecting the storage subsystem logical drives through the host.

2.Check the LEDs. Make note of any Needs Attention LEDs that are on so you can correct the problem when you turn on the power again.

3.Turn off all power supply switches, starting with the DS4700 Express storage subsystem first, and followed by the storage expansion enclosures. Then, unplug the power cables from the storage subsystem.

CAUTION:

The power switch on the power supply and fan unit does not turn off the electrical current supplied to the device. The DS4700 Express Storage Subsystem might also have more than one connection to dc power. To remove all electrical current from the device, ensure that all dc power cords are disconnected from the power supply and fan unit dc input connectors.

Restoring power after an unexpected shutdown

Use the following procedure to restore power to the storage subsystem in a configuration after an unplanned shutdown.

Risk of severe electrical shock – Never turn on the power to any equipment if there is evidence of fire, water, or structural damage. Doing so might cause severe electrical shock

1.After the emergency situation is over or power is restored, visually check the storage subsystem for damage. Is there evidence of damage to any of the storage subsystem components, cables, or equipment attached to the storage subsystem?

v Yes – Do not continue with this procedure. Contact your IBM service representative for assistance. Depending on the current service agreements, you might need to return the equipment to the factory or local service center for repair.

vNo – Go to step 2.

Potential data loss – Before resetting circuit breakers in the cabinet, ensure that the storage subsystem and storage expansion enclosures power switches are turned off. Resetting circuit breakers after an emergency situation while the storage subsystem and storage expansion enclosure power switches are turned on can cause potential data loss because the configuration components might not be powered on in the correct sequence. See “Turning on the storage subsystem” on page 119 for details about the correct power-on sequence.

2.After you check the storage subsystem for damage, ensure that the power switches are in the off position; then plug in the DS4700 Express power cables, if required.

3.Check the system documentation of the hardware devices that you want to turn on and determine the proper startup sequence.

Note: Be sure to turn on all of the storage expansion enclosures and verify that there are not any ESM or power supply and fan unit fault LEDs lit before you turn on the DS4700 Express.

In addition, consider the following items:

vThe storage subsystem supports simultaneous power-up of the system components; however, you should always follow the power-up sequence listed in the “Turning on the storage subsystem section” of

Chapter 4. Operating the storage subsystem 137

Page 169
Image 169
IBM DS4700 manual Restoring power after an unexpected shutdown