EMC VNX5700 - Page 62

64 VNX5700 Hardware Information Guide
Disk-array enclosure
Drive carrier
The disk drive carriers are metal and plastic assemblies that provide smooth, reliable
contact with the enclosure slot guides and midplane connectors. Each carrier has a handle
with a latch and spring clips. The latch holds the disk drive in place to ensure proper
connection with the midplane. Disk drive activity/fault LEDs are integrated into the carrier
(Figure 55 on page 66 and Figure 62 on page 73).
Disk drives
Each disk drive consists of one disk drive in a carrier. You can visually distinguish between
module types by their different latch and handle mechanisms and by type, capacity, and
speed labels on each module. You can add or remove a disk drive while the DAE is
powered up, but you should exercise special care when removing modules while they are
in use. Drive modules are extremely sensitive electronic components.
IMPORTANT
The 4U DAE cannot use disk drives from a 2U or 3U DAE. The 4U DAE employs different
types of SAS, NL-SAS, or Flash disk drives.
Midplane
In a 2U or 3U DAE, a midplane separates the front-facing disk drives from the rear-facing
LCCs and power supply/cooling modules. It distributes power and signals to all
components in the enclosure. LCCs, power supply/cooling modules, and disk drives plug
directly into the midplane.
LCCs
In a 2U or 3U DAE, an LCC supports, controls, and monitors the DAE, and is the primary
interconnect management element. Each LCC includes connectors for input and expansion
to downstream devices. An enclosure address (EA) indicator is located on each LCC
(Figure 61 on page 72 and Figure 68 on page 79)
25
. Each LCC includes a bus (loop)
identification indicator (Figure 61 on page 72 and Figure 68 on page 79).
In a 4U DAE, the primary functionality of an LCC is to be a SAS expander as well as to
provide enclosure services to all the disk drives (60 in all). In other words, the LCC in a 4U
DAE (Figure 75 on page 86) implements a version of the Common Disk Enclosure
Sub-system (CDES) architecture. CDES consists of the PMC-Sierra PM8005 SXP 6G SAS
expander, the Common Disk Enclosure FPGA (CDEF) and supporting logic.
In the 4U DAE LCC, two SAS expanders are available. As previously described, the SAS
expanders are PMC-Sierra SXP36 6G (PM8005, rev C) components. Each expander
functions or operates separately. That is, each expander has its own CDEF and supporting
logic to support 30 drives each. A 4-lane SAS wide port connecting each expander to the
Inter Connect Module (ICM) expander on the same side (A or B) of the 4U DAE is available.
Each expander manages the drives it is connected to. The only shared resources are the
LCC LED and the expander I
2
C (inter-integrated circuit) bus.
25. The EA is sometimes referred to as an enclosure ID.