Hi John,
the main idea behind this UID indicator is to help you to physically identify a server in your computerroom (in a rack or in your datacentre even).
When you logon to the iLO remote management port of the Proliant server, this UID will blink on/off i.e.
If a remote support person (IT helpdesk i.e.) wants to be sure the onsite person i.e. removes the hard disk from the right server i.e. then he can lit the UID constantly via the options in the GUI that you have when you are logged on to the iLO.
The below is taken from the help section in the iLO GUI, this should clarify it for you.
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The Virtual Indicators allow you to monitor, and in some cases control, the state of indicators on the host system, including the Unit Identification Light (UID).
The Unit Identification Light (UID)
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The UID helps you identify and locate a system, especially in high-density rack environments. Additionally, the UID is used to indicate that a critical operation is underway on the host, such as Remote console access or ROM flash.
In general, you control the state of the UID using the UID controls or using the physical UID button on the front of your system (or the back, if supported).
The "current state" (on or off) of the UID is the last state chosen using one of these methods. If a new state is chosen while the UID is blinking, this new state becomes the current state, and takes effect when the UID stops blinking.
NOTE: The Unit ID Light web page does not automatically refresh itself if the state of the actual light changes after the page is loaded. To insure the page accurately reflects the state of the UID Light, click on the Virtual Indicators link to update the page.
UID is blinking
The following circumstances cause the UID to blink:
Remote Console is currently active.
Upgrade of iLO Firmware is in progress.
The UID continues to blink until the circumstances causing it to blink subside. The UID reverts to the current state when the cause of the blinking is gone.
Turn Unit ID On
Clicking this button sets the current state of the UID On. However, blinking the UID overrides this state until the cause has subsided.
The UID current state can also by toggled by pressing the physical button on the front of your system (or on the back, if supported). The UID is blue when lit.
Turn Unit ID Off
Clicking this button sets the current state of the UID Off. However, blinking the UID overrides this state until the cause has subsided.
The UID current state can also be toggled by pressing the physical button on the front of your system (or on the back, if supported). The UID has no color when it is off.
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You could also have a look here in the iLO user manual :
http://h20628.www2.hp.com/km-ext/kmcsdirect/emr_na-c00209014-3.pdf
HTH
Kris
