After four days, the background initialize showed up as completed.
Not sure why the Progress Meter stayed at 0% the entire time, though. That was not reassuring.
I have a similar situation: S5000VSA with 5 x 2TB Westerd Digital drives in RAID 5 array. I have two Virtual drives one of which is the boot drive and the other is the data drive. I recently replaced one of the drives as it was faulty. The system boots but I am unable to access the data drive and it's also stuck at 0% doing the initialize. The data dribe consists of one partition of 6.7TB.
Were you able to access the volumes during the initializing?
I'm getting rather desperate as the data is important. Even if I restore from the latest backup, important data will be lost.