Sun Microsystems Sun StorEdge T3 - Manual (Page 42)

30 Sun StorEdge T3 and T3+ Array Configuration Guide • August 2001
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 4-3 shows a failover configuration.
FIGURE 4-3 Failover Configuration
Primary LUN 0
Failover LUN 1
Primary LUN 1
Failover LUN 0
LUN 1
LUN 0
Application host
FC-AL connection
Interconnect
cables
LAN
Ethernet port
Ethernet
connection
Management host
HBA
Ethernet
connection
Master
Alternate
master
HBA
controller
unit
controller
unit