Fiber Switch Migration

I searched the web and found nothing so decided to document publicly a procedure that has been tested that will allow a person to migrate a system running AIX, using ESS/Shark storage from one fiber switch to another without incurring a downtime.

Start with seeing what the paths are to start with. Below we can see that each LUN has 4 paths.

     root(pshrdb1):/usr/bin>lsvp -a

     Hostname   VG         vpath    hdisk    Location       LUN SN   S  Connection  Size  LSS  Vol  Rank
     --------   --         -----    -----    --------       ------   -  ----------  ----  ---  ---  ----
     mdr        mdrtestvg  vpath0   hdisk10  09-08-01       00530609 Y  R1-B1-H2-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk14  09-08-01       00530609 Y  R1-B2-H1-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk2   00-08-01       00530609 Y  R1-B4-H2-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk6   00-08-01       00530609 Y  R1-B3-H1-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath1   hdisk3   00-08-01       00F30609 Y  R1-B4-H2-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk7   00-08-01       00F30609 Y  R1-B3-H1-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk11  09-08-01       00F30609 Y  R1-B1-H2-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk15  09-08-01       00F30609 Y  R1-B2-H1-ZA 15.8  10   15   1001
 

Get a list of the fiber channel HBA devices

     root(pshrdb1):/usr/bin>lscfg | grep fcs
     + fcs1             U787B.001.DNW8D4D-P1-C1-T1                                      FC Adapter
     + fcs0             U787B.001.DNW8D4D-P1-C3-T1                                      FC Adapter

Take one of the paths off line. It is not important which one. We will check for a “dark” HBA by visually inspecting the back of the box. In this example we will be oflineing and removing fcs0 witch is the HBA plugged into slot 3 (...-C3-... above)

     root(pshrdb1):/usr/bin>datapath set adapter 0 offline
     Success: set adapter 0 to offline

     Adpt#     Name   State     Mode             Select     Errors  Paths  Active
     0    fscsi0  NORMAL  OFFLINE               5413          0      8       0

     root(pshrdb1):/usr/bin>datapath remove adapter 0

     Success: remove adapter 0

     Active Adapters :1

     Adpt#     Name   State     Mode             Select     Errors  Paths  Active
        1   fscsi1  NORMAL   ACTIVE             346238          0      8       8
  

We can now see that some of the paths are now gone. In this example, each LUN went from having 4 paths to only having 2.

     root(pshrdb1):/usr/bin>lsvp -a
     Hostname   VG         vpath    hdisk    Location       LUN SN   S  Connection  Size  LSS  Vol  Rank
     --------   --         -----    -----    --------       ------   -  ----------  ----  ---  ---  ----
     mdr        mdrtestvg  vpath0   hdisk10  09-08-01       00530609 Y  R1-B1-H2-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk14  09-08-01       00530609 Y  R1-B2-H1-ZA 15.8  10   5    1001

     mdr        mdrtestvg  vpath1   hdisk11  09-08-01       00F30609 Y  R1-B1-H2-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk15  09-08-01       00F30609 Y  R1-B2-H1-ZA 15.8  10   15   1001
  

All of the paths have been removed from fcs0 so we are going to delete the device. We do so recursively so that it will automatically remove any dependent device.

     root(pshrdb1):/usr/bin>rmdev -dl fcs0 -R
     hdisk2 deleted
     hdisk3 deleted
     hdisk6 deleted
     hdisk7 deleted
     fscsi0 deleted
     fcnet0 deleted
     fcs0 deleted
  

Here go identify the HBA that is showing no traffic. In this example it will be in slot 3. It should have a slow blinking green light but no amber light. You can now redirect the fiber from the old switch to the new switch for this HBA.

Make sure you have zoned the new switch so that the host and the storage are visible to each other.

Do not proceed below until you have accomplished the fiber move and zoning.

Run cfgmgr to re-discover the deleted HBA and establish a path to the new fiber switch.

      root(pshrdb1):/usr/bin>cfgmgr
  

Check to see that fcs0 has returned

     root(pshrdb1):/usr/bin>lscfg | grep fcs
     + fcs1             U787B.001.DNW8D4D-P1-C1-T1                                      FC Adapter
     + fcs0             U787B.001.DNW8D4D-P1-C3-T1                                      FC Adapter
  

Use the “addpaths” command to instruct SDD to search for and add new paths to the vpath devices.

      root(pshrdb1):/usr/bin>addpaths

See that you have new paths ... and you do!

     root(pshrdb1):/usr/bin>lsvp -a

     Hostname   VG         vpath    hdisk    Location       LUN SN   S  Connection  Size  LSS  Vol  Rank
     --------   --         -----    -----    --------       ------   -  ----------  ----  ---  ---  ----
     mdr        mdrtestvg  vpath0   hdisk2   00-08-02       00530609 Y  R1-B1-H1-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk10  09-08-01       00530609 Y  R1-B1-H2-ZA 15.8  10   5    1001
     mdr        mdrtestvg  vpath0   hdisk14  09-08-01       00530609 Y  R1-B2-H1-ZA 15.8  10   5    1001

     mdr        mdrtestvg  vpath1   hdisk3   00-08-02       00F30609 Y  R1-B1-H1-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk11  09-08-01       00F30609 Y  R1-B1-H2-ZA 15.8  10   15   1001
     mdr        mdrtestvg  vpath1   hdisk15  09-08-01       00F30609 Y  R1-B2-H1-ZA 15.8  10   15   1001
  

Repeat process to move the fiber for the second HBA.