IBM System Storage Subsystem DS5020 - Manual (Page 114)

For other examples of redundant host configurations, see “Fibre Channel host loop
configurations” on page 85.
Fibre Channel and iSCSI connections
A DS5020 storage subsystem Fibre Channel connection consists of up to four host
Fibre Channel loops and a redundant drive Fibre Channel loop. The host Fibre
Channel loops provide the fibre path for host attachment. They can consist of Fibre
Channel cables, SFPs, host bus adapters, Fibre Channel switches, and RAID
controllers. The redundant drive Fibre Channel loop provides the fibre path from the
DS5020 storage subsystem to the hard disk drives (HDDs) in the storage expansion
enclosures. The redundant drive Fibre Channel loop consists of the DS5020
storage subsystem, the storage expansion enclosures, Fibre Channel cables, and
SFPs.
The DS5020 supports redundant drive channel loop configurations. You can build a
redundant drive channel loop by connecting one or more storage expansion
enclosures to the redundant RAID controllers. Then, use dual fiber-optic cables to
connect one storage expansion enclosure to another in a daisy-chain. For more
information, see “Connecting storage expansion enclosures to the DS5020” on page
54.
The DS5020 storage subsystem also supports 1 Gbps iSCSI connectivity. The host
iSCSI connections provide an iSCSI path for host attachment. The connections can
consist of Cat6 Ethernet cables, host bus adapters with iSCSI initiators, or an
Ethernet adapter with Gigabit Ethernet switches and RAID controllers. See “iSCSI
configurations” on page 87 for more information about iSCSI configurations.
Host 1, Host Adapter 1 and 2
Host 2, Host Adapter 1 and 2
Figure 55. Cabling diagram for two redundant host connections
84 IBM System Storage DS5020 Storage Subsystem: Installation, User’s, and Maintenance Guide