The main system documentation - the IBM System Storage DS3500 Implementation Guide - has this text passage in section 4.9.2 - Powering on and off:
In normal circumstances, the DS3500 subsystem would rarely be powered off: it is designed
to run continuously. However, in certain events (scheduled maintenance, controller
replacement on a single controller subsystem, emergency due to unforeseen circumstances,
and so on), you will have to power the subsystem off. Use the same steps as above, but in the
reverse order. If you cannot shut down and power off the host servers, then make sure the
DS3500 logical drives are unmounted at the operating system level.
Note: For controller LED and other hardware information, refer to the appropriate System
Storage DS3500 Storage Subsystem: Installation, User's, and Maintenance Guide manual,
which can be found at the following URL.
Note: A DS3500 subsystem that powers up with no drives installed will get a dummy
FEI. Also, the controllers are accessible through DS Storage Manager and new
(different) firmware can be loaded. This means that certain maintenance actions can be
taken. Drives can be re-added or powered up and the controllers will reboot to load
information out of the DACSTORE on the drives.
Important: Unless it is an emergency, the DS3500 subsystem should never be turned off if
any amber LEDs are lit. You should use the Recovery Guru and other troubleshooting tools
to correct the failure first.
Basically, it boils down to this order:
- shut down all serves using the storage
- switch off the main unit (use the switches on the power supplies on the rear)
- switch off the expansion enclosures, if any
- switch off the storage switches