Upgrade NetApp 8.1.1 7-Mode (FAS3070) to NetApp 9.0 (7-Mode)

Host*> vol status -f

Broken disks

RAID Disk       Device  HA  SHELF BAY CHAN Pool Type  RPM  Used (MB/blks)    Phys (MB/blks)
---------       ------  ------------- ---- ---- ---- ----- --------------    --------------
predict failure 0c.74   0c    4   10  FC:B   -  FCAL 15000 560000/1146880000 560208/1147307688

So, to replace this disk, is there a need to fail it? What is the difference between predictive failure, and failed disk?

Thanks