IBM 2145UPS-1U Hardware Installation Manual page 47

Note: See "MAP 5800: Light path" in the IBM System Storage SAN Volume
Controller: Service Guide to help you to isolate the faulty FRU.
A system-led error LED is also on the rear of the SAN Volume Controller.
Information-Error LED
When the information-error LED is lit, a non-critical event has occurred.
Check the light path diagnostics panel and the error log. Light path diagnostics are
described in more detail in the light path maintenance analysis procedure (MAP).
Location LED
The SAN Volume Controller does not use the location LED.
Hard disk drive activity LED
When it is lit, the green hard disk drive activity LED indicates that the hard disk
drive is in use.
Power LED
The green power LED indicates the power status of the SAN Volume Controller.
The properties of the green power LED are as follows:
Off One or more of the following are true:
v No power is present at the power supply input
v The power supply has failed
v The LED has failed
On The SAN Volume Controller is powered on.
Flashing
The SAN Volume Controller is turned off but is still connected to a power
source.
Note: A power LED is also on the rear of the server.
Power control button
The power control button switches on or switches off the main power to the SAN
Volume Controller.
To turn on the power, press and release the power control button.
To turn off the power, press and release the power control button. For more
information about how to power off the SAN Volume Controller node, see "MAP
5350: Powering off a SAN Volume Controller node" in the IBM System Storage SAN
Volume Controller: Service Guide.
Note: When the node is operational and the power control button is pressed, the
SAN Volume Controller indicates on its front panel that it is powering off
and writes its control data to its internal disk. This can take up to five
minutes. If the power control button is pressed and not released, an
immediate power off is performed without writing the SAN Volume
Controller control data to disk. Service actions are then required to make the
SAN Volume Controller operational again. Therefore, when powering off,
you should not press and hold the power control button for more than two
seconds.
Chapter 2. SAN Volume Controller overview
9