Can try the following script:
==============================
#!/bin/ksh
#
# ----------------------------------------------------------------------------
#
#
# Function: mirror hdisk0 to hdisk1
#
# ----------------------------------------------------------------------------
echo
echo …………… ‘cfgmgr’ will bring the second disk to available………
cfgmgr
echo
echo ................…. CHECKING THE size of BOOT DISK ......................
lsvg rootvg
echo
echo ............... CHECKING FOR SCSI-ID AND LOCATION ....................
lsdev -Cc disk
echo
echo ............. CHECKING that DESTINATION DISK IS bootable (1) .......
bootinfo -B hdisk1
echo
echo ...........……….. EXTEND rootvg on ADDITIONAL disk .................
extendvg rootvg hdisk1
echo ................…………….now MIRROR rootvg .............................
mirrorvg rootvg hdisk1
echo ............. RUNNING bosboot FOR BOOT DISK ..................
bosboot -a -d /dev/hdisk0
echo
echo ..............……… BOOTLIST WILL BE DEFINED NOW .........................
bootlist -m normal hdisk0 hdisk1
echo ................………. QUORUM will be changed to off ...........................
chvg -Q 'n' rootvg
echo ..................………… check final rootvg .........................
lsvg rootvg
echo ……….. …… SYSTEM MIRROR SUCCESSFUL ………….
STATUS=0
exit
"Long live king Moshiach !"
h