IBM DS6000 Series manual Power subsystem RAS, DS6000 switched disk connections

paths) since two paths to the expansion controller would be available for the remaining controller.

disk

exp

disk

contrl

disk

contrl

disk

exp

RAID controller 0 RAID controller 1

device adapter		device adapter
chipset			chipset
loop 1		loop 0		loop 1
	loop 0
engine	engine	engine		engine

Fibre channel switch		Fibre channel switch
Enclosure midplane
	Midplane

Figure 3-5 DS6000 switched disk connections

3.4 Power subsystem RAS

As discussed in Chapter 2, “Components” on page 23, the DS6000 is equipped with two BBUs and two power supplies. This provides redundancy in case of either an external power failure or an internal power subsystem failure. The DS6000 is able to control the state of the power supplies in the expansion enclosures via in-band commands sent through the device adapter Fibre Channel connections.

In the event of a BBU failure, the RAID controller that relies on that BBU for data protection will remove itself from service and go offline until its BBU is fully charged. If both BBUs were to fail, then the entire system would have to go offline until the problem is corrected. This possibility is highly unlikely.

All power components are hot plugable and can usually be replaced without employing the DS Storage Manager GUI. If more information is needed, however, the GUI could be employed, as described in “Example 2: Using the GUI to replace a power supply” on page 57.

56DS6000 Series: Concepts and Architecture