unmirrorvg -c 1 rootvg hdisk0
bosboot -ad hdisk1
sysdumpdev -l
sysdumpdev -Pp /dev/hd6
rmlv hd7
reducevg rootvg hdisk0
extendvg -f rootvg hdisk0
mirrorvg -S -c 2 rootvg
bosboot -ad hdisk0 ; bosboot -ad hdisk1
bootlist -m normal -o
bootlist -m normal hdisk0 hdisk1
sysdumpdev -l
sysdempdev -e
mklv -y hd7 -t sysdump rootvg 10 hdisk0
sysdumpdev -Pp /dev/hd7
To parallelize the mirror copy you can specify how many simultaneous LPs to sync. This will speed up your mirror.
If you set the parameter NUM_PARALLEL_LPS=24 for example in /etc/environment then logout and login again, do a: syncvg -v rootvg &
# mklv -y hd5 -t boot rootvg 1 hdisk0 # bosboot -ad /dev/hdisk0 -l hd5 # bootlist -m normal -o