R730xd Unable to recognize hard drive due to power outage

Hi,

Let's try at first performing a drain flea power. 

1. Power the server down.  
2. Disconnect server from all power cables, Network cables. 
3. Hold down the power button continuously for at least 10 seconds.  
4. Insert power cabless and network cables back to the system.  
5. Wait about 2 minutes before powering on the server for iDRAC to be refreshed.
6. Power the system on. 

After experiencing a 20-minute power outage, the server was reconnected; however, the initial problem persisted. To address this, I executed a reset of the iDRAC via the Quick Launch Tasks on the overview page. Following a power cycle and subsequent login, the storage section was operational once again.

And lastly you can do repurpose or retire system as on this video: https://dell.to/4eDQGfJ

Hope that helps!