Option 1:
Replace disk1 with a high capacity disk -> Rebuild the RAID -> Wait 18-24 hours for the rebuild to complete.
Once done,
Replace disk2 with a high capacity disk -> Rebuild the RAID -> Wait 18-24 hours for the rebuild to complete.
Once done,
Replace disk3 with a high capacity disk -> Rebuild the RAID -> Wait 18-24 hours for the rebuild to complete.
Once done,
Replace disk4 with a high capacity disk -> Rebuild the RAID -> Wait 18-24 hours for the rebuild to complete.
Then delete and recreate the RAID -> Wait 18-24 hours for the rebuild to complete.
Only once you delete/recreate the RAID will you see the high capacity.
Total time -> 90 to 120 hours.
Option 2:
Or get the recovery file for the LS-QVL -> Replace all the disks at once and load the recovery file to install the OS onto the new disks.
Total time for this -> 30 mins -> 1 hour.