IBM System Storage DCS3700 Installation, User's, And Maintenance Manual page 128

You need the backup to restore data on the DDMs later in this procedure.
Attention: When you handle static-sensitive devices, take precautions to avoid damage from static
electricity. For details about handling static-sensitive devices, see "Handling static-sensitive devices"
on page 25.
4. Unpack the new DDMs.
Set the DDMs on a dry, level surface away from magnetic fields. Save the packing material and
documentation in case you need to return them.
5. Perform the following steps:
a. Stop all I/O activity to the storage subsystem and attached storage expansion enclosures. Make
sure of the following:
1) All of the green Drive activity LEDs on the front of the storage subsystem are not flashing.
2) The Cache active LEDs are off. Refer to "Checking the LEDs" on page 73 for the location of
the Cache active LEDs.
b. If applicable, use the operating system software to disconnect the storage subsystem logical
drives from the host before you power off the storage subsystem.
Attention: To turn off all power to the storage subsystem, you must turn off both power-supply
switches and disconnect both power cords. Use the procedure in step 6 for the proper shutdown
sequence.
6. Turn off the power to each device based on the following shutdown sequence:
a. Turn off power to the host before you turn off power to the storage subsystem. If the host must
stay powered on to support an existing network, see the operating system documentation for
information about disconnecting the storage subsystem logical drives from the host before the
storage subsystem is powered off.
b. Turn off power to the DCS3700 storage system before you power off the DCS3700 expansion
enclosure. Turn off both power supply switches on the back of the storage subsystem.
Statement 5:
CAUTION:
The power control button on the device and the power switch on the power supply do not
turn off the electrical current supplied to the device. The device also might have more than
one power cord. To remove all electrical current from the device, ensure that all power cords
are disconnected from the power source.
c. Turn off power to other supporting devices (for example, management stations, Fibre Channel
switches, or Ethernet switches).
7. Use the procedures in "Replacing hot-swap hard disk drives" on page 103 to remove the DDMs that
you want to replace. Use the procedures in "Installing hot-swap hard disk drives" on page 101 to
install the new DDMs into the DCS3700.
8. After you install all the new DDMs, check the system documentation for the hardware devices that
you intend to power up, and then determine the proper startup sequence. Use the following
power-on sequence, where applicable:
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IBM System Storage DCS3700: Installation, User, and Maintenance Guide