IBM System Storage Subsystem DS5020 - Manual (Page 37)

Enhanced Disk Drive Modules (E-DDMs)
The hot-swap drive bays that are accessible from the front of your storage
subsystem are shown in Figure 1.
The DS5020 supports both Fibre Channel (FC) and SATA E-DDMs intermixed in the
storage subsystem drive chassis. The DS5020 supports up to sixteen 4 Gbps FC or
3 Gbps SATA E-DDMs.
SATA E-DDMs have an ATA translator card that converts the Fibre Channel protocol
interface of the DS5020 drive channel or loop into the hard drive SATA protocol
interface. It also provides dual paths to the SATA drive for drive CRU path
redundancy. Each drive, ATA translator card (also referred to as interposer card),
and carrier assembly are called SATA E-DDM CRUs. The Fibre Channel E-DDMs
consist of the Fibre Channel and the carrier assembly (drive tray).
Install E-DDM CRUs in the 16 drive bays on the front of the storage subsystem
from the leftmost slot (slot 1) to the rightmost slot (slot 16). When an E-DDM is
installed, the drive and tray slot designation is set automatically. The hardware
addresses are based on the enclosure ID, which is set by the controller software,
and on the E-DDM physical location in the storage subsystem.
The DS5020 storage subsystem drive channel operates at a 4 Gbps Fibre Channel
interface speed. Make sure that the DS5020 enclosure speed switch is set correctly
for 4 Gbps Fibre Channel E-DDM CRUs. The DS5020 storage subsystem SATA
E-DDM CRUs have an ATA translator card that converts E-DDM 3 Gbps SATA drive
interface protocol to a 4 Gbps Fibre Channel interface protocol. Operate these
SATA E-DDMs at 4 Gbps Fibre Channel operating speed.
Note: Even though the DS5020 has a 2 or 4 Gbps Fibre Channel Link Rate switch
that can be used to set the drive channel speed at 2 Gbps, the link rate
speed must be set to 4 Gbps. The DS5020 supports only 4 Gbps FC speed
in the drive channel. See “Verifying the link rate setting” on page 136for
more information.
The Link Rate switch on the DS5020 storage subsystem and the storage expansion
enclosures connected to it must have the same setting.
There are no serviceable parts in an E-DDM CRU. If it fails, it must be replaced in
its entirety (E-DDM, ATA translator card, bezel, and tray). The DS5020 drive tray is
not interchangeable with the drive tray of other DS4000 storage subsystems such
as DS4100 or DS4300 storage subsystems. The DS5020 E-DDM option CRUs are
not interchangeable with those of the DS4200 Express and EXP420. When
replacing an E-DDM CRU, be sure to order and install the correct E-DDM CRU.
Figure 1. DS5020 hot-swap drive bays
Chapter 1. Introduction 7