It says there is a hard drive that is defunct however the system does boot up but the application does not work and I think it is due to the oracle not being able to run. How to recover from the data corruption due to the drive failure?
Well lets make some assumptions
1. You have a Raid 5 System
2. You only have 3 drives in the Raid ARRAY
3. Only 1 drive has failed
To fix the problem you should only need to Replace the Failed Drive
Then start the raid management software or bios
Rebuild the array
If you have more than 1 drive failed in a RAID 5, and still must recover the data it is possible. But very expensive. Still fixable however.
A RAID 5 array would still allow you to access and use the data with one drive having failed. So, since your application isn't functioning I'm assuming that you've lost more than one hard drive in a RAID 5 array OR you've lost both drives in a two drive RAID 1 array OR you've lost one (or more) hard drive(s) in a RAID 0 array OR you've lost a lethal combination of drives in a RAID 10 array. Any way you slice it you will have to replace the failed drives and restore the data from a backup. The only other "safe" option is "roll the dice" with a data recovery service (no guarantees of success) and (will be much more costly than it would have been to have an active backup system in place). You can always try to recover the data yourself; there are various techniques, none of which are safe and WILL make data recovery service less likely a successful option. Good luck!
Usually answered in minutes!