IBM DS8000 manual Enclosure

Single pathed host

HBA

Server owning all even LSS logical volumes

RIO-G

RIO-G

HP HP HP HP		HP HP HP HP	HP HP	HP HP
Fibre		Fibre	ESCON	ESCON
channel		channel	Slot 4	Slot 5
Slot 1		Slot 2
RIO-G	I/O enclosure 2				RIO-G

RIO-G	I/O enclosure 3				RIO-G
Slot 1		Slot 2	Slot 4		Slot 5
Fibre		Fibre	ESCON	ESCON
channel		channel
HP HP HP HP		HP HP HP HP	HP HP		HP HP

RIO-G

RIO-G

Server owning all odd LSS logical volumes

Figure 4-5 Single pathed host

It is always preferable that hosts that access the DS8000 have at least two connections to separate host ports in separate host adapters on separate I/O enclosures, as depicted in Figure 4-6 on page 73. In this example, the host is attached to different Fibre Channel host adapters in different I/O enclosures. This is also important because during a microcode update, an I/O enclosure may need to be taken offline. This configuration allows the host to survive a hardware failure on any component on either path.

72DS8000 Series: Concepts and Architecture