Sun Microsystems T3 manual Host Multipathing Management Software, Lun

Host Multipathing Management Software

While Sun StorEdge T3 and T3+ arrays are redundant devices that automatically reconfigure whenever a failure occurs on any internal component, a host-based solution is needed for a redundant data path. Supported multipathing solutions include:

■The DMP feature in VERITAS Volume Manager

■Sun Enterprise Server Alternate Pathing software

■Sun StorEdge Traffic Manager software

During normal operation, I/O moves on the host channel connected to the controller that owns the LUNs. This path is a primary path. During failover operation, the multipathing software directs all I/O to the alternate channel’s controller. This path is the failover path.

When a controller in the master controller unit fails, the alternate master controller unit becomes the master. When the failed controller is repaired, the new controller immediately boots, goes online and becomes the alternate master controller unit. The former alternate master controller unit remains the master controller unit.

Note – The multipathing software solution must be installed on the application host to achieve a fully redundant configuration.

FIGURE 4-3shows a failover configuration.

LUN 1
Alternate		Ethernet
master		connection
controller
unit		Application host
Interconnect		HBA	Primary LUN 1
cables
			Failover LUN 0
LUN 0			Primary LUN 0
Master
controller		HBA	Failover LUN 1
unit
FC-AL connection
	Ethernet
	connection		Ethernet port
		LAN
		Management host
FIGURE 4-3	Failover Configuration

30 Sun StorEdge T3 and T3+ Array Configuration Guide • August 2001