IBM Midrange System DS4000 Series Hardware Manual page 481

In Example 7-13, we see a bad condition example, where:
Both paths to controller B failed.
LUN0 is owned by controller A, which is in the Optimal state.
LUN1 is owned by controller B, which is in the failed state. LUN1 has been taken over by
controller A.
To correct these path issues, set the paths to controller B.
To relate the devices detected by Linux to the logical drives configured and mapped to your
host in the DS5000, use the mppUtil utility. You can use the LUN number listed and the WWN
string to determine the corresponding logical drive in your DS5000.
Example 7-13 mppUtil -g1 - controller failover
[root@TC-2008 ~]# mppUtil -g0
Hostname = TC-2008
Domainname = (none)
Time = GMT 10/01/2009 19:27:28
MPP Information:
----------------
ModuleName: ITSO_5020
VirtualTargetID: 0x000
ObjectCount: 0x000
WWN: 60080e500017b5bc000000004a955e3b
ModuleHandle: none
FirmwareVersion: 7.60.13.xx
ScanTaskState: 0x00000000
LBPolicy: LeastQueueDepth
Controller 'A' Status:
-----------------------
ControllerHandle: none
UTMLunExists: N
NumberOfPaths: 2
Path #1
---------
DirectoryVertex: present
PathState: OPTIMAL
PathId: 77020000 (hostId: 2, channelId: 0, targetId: 0)
Path #2
---------
DirectoryVertex: present
PathState: OPTIMAL
PathId: 77030000 (hostId: 3, channelId: 0, targetId: 0)
Controller 'B' Status:
-----------------------
ControllerHandle: none
UTMLunExists: N
HW problem
NumberOfPaths: 2
Chapter 7. Advanced maintenance, troubleshooting, and diagnostics
SingleController: N
ScanTriggered: N
AVTEnabled: Y
RestoreCfg: N
Page2CSubPage: Y
ControllerPresent: Y
Failed: N
FailoverInProg: N
ServiceMode: N
Present: Y
Present: Y
ControllerPresent: Y
Failed: Y<--indicates
FailoverInProg: N
ServiceMode: N
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