Oracle on AIX -Mirrored Data

Hi

Our Oracle v8.05 database server is running on the IBMRS6000 AIXv 4.3.

Oracle tables are mirrored across 2×9.1GB harddisk under one volume group. If we have run out of space and is adding in 2X18.2GB harddisk, what would be the proper wayto backup our existing data and restoring it onto the new harddisks. Is it safe to backup the volume group and restoring it after the installation of the new disks ? My worry is data integrity may be affected.

Hope that you can advise.

Thank you.

SL