IBM BladeCenter S Installation And User Manual page 21

v A SAS expansion card in each of the blade servers, which provides access
through the SAS I/O modules in I/O module bays 3 and 4 to the SAS or SATA
hard disk drives in each disk storage module. This only applies to the 6-disk
storage module.
There is one LED on each disk storage module:
Fault Solid (amber) when there is a disk storage module failure.
There are two LEDs on each hard disk drive:
Green Flashing when an operation, such as a read or a write, is being performed.
Amber
Flashing when the hard disk drive is being rebuilt (fast blink) or identified
(slow blink).
Note: When power is restored to the BladeCenter S chassis after a
complete loss of power and you have implemented the hard disk drives as
a mirrored array, the fault light will blink as the hard disk drive is being
resynchronized.
This resynchronization occurs because the blade servers are attempting to
power on before all of the disk storage modules and SAS connectivity
modules or SAS RAID controller module are powered up and available.
The mirrored array is accessible during resynchronization although
performance may be slightly slower.
Solid when there is a drive failure.
Media tray
The media tray contains the DVD drive (which can be either a CD-RW/DVD-ROM
drive or a DVD/RW drive) and two USB v2.0 ports, which are shared by the blade
servers. The media tray also contains two battery backup units, which provide
backup for SAS RAID controller modules cache.
Note: The port on the side of the media tray is reserved for future use.
9
Chapter 1. Introduction