Sun Microsystems 3900, 6900 manual Sun Proprietary/Confidential Internal Use Only

FIGURE 2-4,

The host, using multipathing software, is presented with two primary (active) paths for each LUN, allowing the host to route I/O through either or both HBAs.

If a path failure occurs before the second tier of Sun StorEdge network FC switch-8 and switch-16 switches, one of the paths is disabled—but the other path continues sending I/O as it normally would and takes over the entire load. Refer to

which illustrates a path failure before the second tier of switches.

No Sun StorEdge T3+ array failure is noted because of the redundant path, by way of the Sun StorEdge network FC switch-8 and switch-16 switch T ports.

LUN0 - 10G

Active-MPDrive0

LUN1 - 10G

Active-MPDrive1

Host with HBA-0 and HBA-1

LUN0 - 10G

Active-MPDrive 0

LUN1-10G

Active-MPDrive1

Switch

FAILURE

Switch

SAN

Database	Virtualization
	Engine (2)
MPDrive
Carved LUNs
Masking

Storage I/O and

Virtualization Engine Communications Traffic

Switch

Switch

LUN0 - 500G Passive-Master

Logical Multipath Drive MPDrive 0

LUN0 - 500G Active-Master

LUN1 - 500G
Active -	Logical Multipath
Alternate Master
	Drive MPDrive 1

LUN1 - 500G

Passive -

Alternate Master

T3ES

(Master)(0A - 1P)

(Alternate Master) (1A - 0P)

FIGURE 2-4Path Failure—Before the Second Tier of Switches

14 Sun StorEdge 3900 and 6900 2.0 Series Troubleshooting Guide • March 2003

Sun Proprietary/Confidential: Internal Use Only