how to increase space NCR 4.0

Hello,

I have a little problem, I would like to know how to add disk space on an NCR version 4 and above all whether it still contains vdisk space

smp001-4 4.0 3.0

/dev/dsk/vdisk15 3940505 3807833 132672 97% /data

in the dktab :

/dev/dsk/vdisk15 mirror 2 128
/dev/dsk/c100t3d0s8 0 7881010
/dev/dsk/c100t4d0s8 0 7881010

Thx