How do I convert a single path boot from SAN RHEL system to multipath in RHEL 5?

Issue

• There is an installed system that was recently upgraded with multiple HBAs. We now have multipath storage available and would like to reconfigure the system to take advantage of the additional paths. How can this be done?

• The system was configured to boot from SAN. During OS installation root lvm/filesystem were created using sub paths - /dev/sdxx. Is it possible to migrate from single path /dev/sdxx to device-mapper-multipath devices viz. /dev/mapper/mpathX after OS installation??

  $ lvs_-a_-o_devices
    LV          VG     Attr   LSize      Devices                                        
    LogVol00    rootvg -wi-ao   6.00G    /dev/sdbt2(0)                     <--- root lvm volume created using underlying sub path                             
    LogVol01    rootvg -wi-ao  10.00G    /dev/sdbt2(352)                                
    LogVol02    rootvg -wi-ao   5.00G    /dev/sdbt2(674)