Our Software RAID was not designed for any failure rate. If you are concerned then you can use your RAID controllers RAID set capabilities. For your RAID 6 requirements please review your RAID controller specifications. When adding more capacity to your existing RAID set you will need to migrate these drives to your RAID controller then use our Physical Volume resizing function. Then add this to your existing Volume Group this can be done very quickly. You can test this with the Demo-CD along with other functions. Please review the manual as well to properly understand our product.