FAQ-If Storage Devices and the AIX Application Server Perform Networking Using a Fibre Channel Switch, What Operations Can Be Performed to Ensure that the Multipathing Software Runs Normally After the Software Is Installed on the Application Server

Publication Date:  2015-07-24 Views:  213 Downloads:  0
Issue Description
If storage devices and AIX application server perform networking using a Fibre Channel switch, what operations can be performed to ensure that multipathing software runs normally after the software is installed on the application server?

Solution
After the multipathing software is installed, modify the following properties of the Fibre Channel HBA before restarting the application server.
  • Set fc_err_recov of the HBA to fast_fail.
fast_fail is used to recover a fast fail. When the fast_fail function is enabled, the failover duration of paths can be shortened.

NOTE:
fast_fail must be lower-case letters.
  • Set dyntrk of the HBA to yes.
     
dyntrk is used for dynamic tracking. After the dyntrk function is enabled, the host HBA can identify that a link status has been changed, and automatically reconfigure the link if you remove or insert optical fibers in the same domain on a Fibre Channel switch.

NOTE:
dyntrk must be lower-case letters.

Delete the sub-devices on fscsi as follows before modifying the properties.

1.  Query the current facsi device.


# lsdev -Cc driver|grep fscsi
fscsi0   Available 06-08-01    FC SCSI I/O Controller Protocol Device
fscsi1   Available 0B-08-01    FC SCSI I/O Controller Protocol Device


2.  Query properties of the current HBA.

# lsattr -El fscsi0
attach       switch    How this adapter is CONNECTED         False
dyntrk       yes       Dynamic Tracking of FC Devices        True
fc_err_recov fast_fail FC Fabric Event Error RECOVERY Policy True
scsi_id      0x20a00   Adapter SCSI ID                       False
sw_fc_class  3         FC Class for Fabric   


NOTE:
If fc_err_recov and dyntrk of the current HBA have been set to fast_fail and yes respectively. Directly go to next step.


3.  Check whether sub-devices exist on the fscsi device.

# lsdev -p fscsi0
sfwcomm0 Available 06-08-01-FF Fibre Channel Storage Framework Comm


4.  Delete corresponding sub-devices according to queried results.

# rmdev -dl sfwcomm0
sfwcomm0 deleted


5.  Modify HBA properties.

# chdev -l fscsi0 -a fc_err_recov=fast_fail
fscsi0 changed
chdev -l fscsi0 -a dyntrk=yes
fscsi0 changed

END