7914Cabling2-1908.fm Draft Document for Review March 28, 2011 12:24 pm
132  IBM System Storage DS3500: Introduction and Implementation Guide
of one power source does not cause an unexpected power down event of the entire 
enclosure.
4.9.2  Powering on and off 
A typical DS3500 configuration includes the following components: 
ň° Host servers 
ň° DS3500 storage subsystem 
ň° EXP3500 enclosures 
ň° (Optional) SAN infrastructure 
Powering on 
It is important that you follow the correct power-on sequence, or the system might not work 
properly. Power the components on in this order: 
1. SAN switches should be powered on first. In a typical SAN environment, the SAN switches 
are kept up and running all the time and are typically only powered down in case of 
emergency. 
2. EXP3500 enclosures are next. Turn on the switches on both power supplies on each 
EXP3500 enclosure. Allow enough time for the enclosures to fully power up, which can 
take several minutes.
3. When all EXP3500 enclosures are up and running, then power on the DS3500. Be aware 
that large configurations can take up to ten minutes to fully power up. 
4. Finally, power on all the host servers when the DS3500 is fully online. You should check 
the status of the DS3500 by using Storage Manager from your out-of -band management 
station.
Powering 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.
http://www-304.ibm.com/systems/support/
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 some 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.