.SAN design reference guide Vol. 1-5 785350-001

Figure 80 EVA8100 two independent, dual-redundant SAN configuration
25132a
Fabric A
Fabric B
Fabric C
Fabric D
SAN 1 SAN 2
Dual-channel HBA configurations
Use dual-channel HBAs when the number of server PCI slots is limited. Most installations are
configured as shown in Figure 81 (page 233) or Figure 82 (page 233). Both configurations are
implemented using a single PCI slot to provide access to the same targets or LUNs, or to a different
set of storage targets or LUNs through separate ports on the HBA.
Each dual-channel HBA provides greater performance than a single-channel HBA for a single PCI
slot.
Target ranges are examples only. The number of storage controller targets and LUNs associated
with each accessible target is operating system dependent.
Figure 81 (page 233) shows two HBA paths connected to the same Fibre Channel switch.
Figure 81 Single PCI slot with dual-channel HBA and one switch
25137b
Targets A, B,...
Targets C, D,...
Port 1 Port 2
Dual-channel
HBA
The configuration shown in Figure 82 (page 233) provides increased availability during a single
switch failure. For example, availability to a specific set of targets is increased by configuring
access to targets A, B on both paths.
Figure 82 Single PCI slot with dual-channel HBA and two switches
25138b
Targets A, B,...
Targets C, D, or
Targets A, B,...
1 2
Port 1 Port 2
Dual-channel
HBA
Cabling 233