Sun Microsystems StorEdge 3000 Series, Installation, Operation And Service Manual

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Chapter 1 Product and Architecture Overview 1-9
In a dual RAID controller configuration, both RAID controllers have the same
channel designators, due to the architecture of the loops within the chassis. Each
host and drive channel of the top RAID controller shares a loop with the matching
channel on the bottom RAID controller. For example, Channel 0 of the top RAID
controller shares the same loop as channel 0 of the bottom RAID controller. This
provides four separate loops for direct connectivity to hosts, expansion chassis, or
hub and switch devices.
Each host and drive loop includes multiple components. Each I/O board contains
FC-AL loops and port bypass circuits that are associated with three components: a
channel on the RAID controllers, the SFP port residing within the I/O board, and a
connection to the opposite I/O board. This architecture provides a data path for both
RAID controllers to either the top or bottom SFP port on a given channel. Plugging
an SFP transceiver into a port enables external connections to that port. The optical
connector used is the low-profile LC connector. Plugging and unplugging SFP
connectors into ports is straightforward and easy.
The configuration of a single RAID controller configuration is slightly different. The
connection to the lower I/O board does not exist; however, the same number of
loops are available.
1.5.2 Disk Drive FC Architecture
Channels 2 and 3 are disk drive channels only and cannot be used as host channels.
In the disk drive FC architecture, channel 2 from both controllers appears on the
upper I/O board and channel 3 from both controllers appears on the lower I/O
board.
The components residing on the disk drive loops are:
■
Channel 2 or 3 (depending upon I/O board being reviewed) from one controller
■
Channel 2 or 3 from the second controller
■
Two SFPs
■
Disk drive loop A for channel 2 or disk drive loop B for channel 3
■
The SES logic
Note – RAID array channels 0, 1, 4, and 5 can be host or drive ports; by default, they
are host ports. The CH2 and CH3 ports are dedicated drive ports and cannot be used
as host ports.