Here's a case that multiple physical paths exist in a fibre channel environment but only one path can be viewed on the host.
Symptom
On a Fibre Channel network where the QLogic cards are used, after UltraPath is installed, the multiple physical links are connected and ports are added and mapped to the host. However, only one path can be viewed on the host.
Fault Diagnosis
Certain versions of the QLogic driver have the failover function. When the system is started, the driver filters out redundant paths. Therefore, redundant path information cannot be viewed.
Solution
Step 1: Run the lsmod |grep ^qla command to view the QLogic driver name.
Then run the modinfo QLogic driver name| grep ql2xfailover command to check whether the QLogic driver of this version supports the failover function.
If the output information has the failover parameter ql2xfailover, the failover function is supported.
Step 2: Run the cat /sys/module/qla2xxx/parameters/ql2xfailover command to check whether the failover function of the driver is enabled.
The value 1 indicates that the failover function is enabled while 0 indicates that the failover function is disabled.
Step 3: Modify the /etc/modprobe.conf.local or /etc/modprobe.conf system file.
Add a line (options qla2xxx ql2xfailover=0) to the end of the file to disable the failover function of the QLogic driver.
Step 4: Run the upadm start updateimage command to update the UltraPath startup items.
Step 5: Restart the host to enable the configuration to tae effect.
Hope this will help you solve similar cases.
