Powering On The Storage Subsystem - IBM Midrange System DS4000 Series Hardware Manual

4.8.2 Powering on the storage subsystem

Before powering on your storage subsystem, make sure you have your hardware installed
correctly. In particular, check whether your system has a speed switch located on the front of
the system. This should be set to 2 GB or 4 GB and match the speed of the drives installed in
that enclosure. You might also want to check, if you have multiple old expansion units, that all
of them have a different enclosure ID assigned. New expansion enclosures do not require a
switch setting for the enclosure ID, because they are automatically assigned at first power on.
For specific details, see 3.4, "DS5100 and DS5300 storage subsystems" on page 29.
When turning power on or off, a certain order must be followed on the DS5000 storage
subsystem.
The drives attached to the storage subsystem must be available when the storage subsystem
is powered up. In other words, when expansion enclosures are attached to a storage
subsystem, the expansions must be powered up first.
Important: Always power up the expansion enclosures first. The controllers in the storage
subsystem might not recognize the correct configuration if the drives are powered up after
the storage subsystem.
The Fibre Channel and Ethernet hubs and switches, if installed, must be powered on before
the host to ensure proper loop initialization. When connecting your DS5000 storage
subsystem ports to a SAN switch, or directly to a host, match whenever possible the
maximum speed of the ports, that is, avoid connecting an 8 Gb SFP to a 2 Gb switch or host
bus adapter, for example.
The power up procedure includes the following steps:
1. Turn on the expansion enclosures.
2. After the last enclosure is powered on, wait for all the disks to be ready (steady green LED
for each disk).
3. Turn on the SAN or Ethernet switches (if attached).
4. Turn on the DS5000 storage subsystem.
5. Turn on the host application server.
The power-down procedure includes the following steps:
1. Turn off the host application server.
2. Turn off the DS5000 storage subsystem.
3. Turn off hubs/switches (if attached).
4. Turn off the expansion enclosures.
Important: Ensure that your system is in an optimal state before you shut it down. Never
turn the power off if any fault light is lit. Be sure to resolve any error conditions before you
shut down the system.
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IBM Midrange System Storage Hardware Guide