1. 2 ports were connected to fabric. port1 was “active” and port2 was “enabled”
test6:~ # multipath -l
mpath331 (SAreca_ARC-1220-VOL#00_54047306) Areca,ARC-1220-VOL#00
[size=1043G][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][active]
 \_ 3:0:0:0 sdb 8:16  [active][undef]
\_ round-robin 0 [prio=0][enabled]
 \_ 2:0:0:0 sda 8:0   [active][undef]

2. The IO was running on port1.

3. Removed ib cable from port1. 

4. 2 minutes later, the path at port1 was failed then port2 picked up the IO
test6:~ # multipath -ll
mpath345 (SAreca_ARC-1220-VOL#00_54047306) ,
[size=1043G][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][enabled]
 \_ #:#:#:# -   #:#   [failed][faulty]
\_ round-robin 0 [prio=0][active]
 \_ 2:0:0:0 sda 8:0   [active][ready]

5. Added the IB cable back to port1.

6. The log file was showed "add path" and the new major, minor numbers (8:32).

7. The scsi_host “sdc 8:32” was created.  However, the new path did not show on the current topology.
test6:~ # multipath -v2 -d
: checker msg is "readsector0 checker reports path is down"
mpath346: failed to access path
create: mpath346 (SAreca_ARC-1220-VOL#00_54047306) Areca,ARC-1220-VOL#00
[size=1043G][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][undef]
 \_ 2:0:0:0 sda 8:0   [active][ready]
\_ round-robin 0 [prio=0][undef]
 \_ 7:0:0:0 sdc 8:32  [undef][ready]

test6:~ # multipath -ll
mpath345 (SAreca_ARC-1220-VOL#00_54047306) ,
[size=1043G][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][enabled]
 \_ #:#:#:# -   #:#   [failed][faulty]
\_ round-robin 0 [prio=0][active]
 \_ 2:0:0:0 sda 8:0   [active][ready]