How to clone or mirror your AIX OS larger disk to smaller disk ?

hello folks,

I have a 300GB ROOTVG volume groups with one filesystem /backup having 200GB allocated space

Now, I cannot alt disk clone or mirrorvg this hdisk with another smaller disk. The disk size has to be 300GB; I tried alt disk clone and mirrorvg , it doesn't work. you cannot copy LVs as operating system has some lv which cannot be copied other than mirrorvg..

is there a way to make another smaller hdisk = 10GB have a copy of only the AIX operating system from the already existing hdisk which is 300GB ?

thanks