Ashevis, Are you currently still able to boot to the array? If so then we need to run a Dset on the server to check the raid controllers log. It could actually be a punctured parity stripe. Which is when a Predicted failure's bad blocks are rebuilt across the remaining good drives. Which is what can cause both to be showing a Predicted Failure. Now it can also be that the drives just hit the threshold around the same time and flagged both. We will be able to tell which with the controller log.  If it is a punctured parity stripe then you would need to recreate the array and OS and restore from backup. No question. If it is just that they are flagged then it would a chance of recovery by rebuilding each, but there is still a risk of the pred fail transferring bad blocks, during the rebuild, to the new drive. Which causes a puncture. So in short the best course of action would be to backup the data,  recreate, and do a restore.  
I have a Poweredge R210 with Raid 1 on a PERC H200 controller.  I ran the check consistency task on the virtual disk and got a bunch of Error ID 2350's in the alert log reading : There was an unrecoverable disk media error during the rebuild or recovery operation --these were recorded for both disk 0 and disk 1. Is there any way to rebuild the mirror on this?  Both hard drives are showing 'failure predicted' in OMSA.  From what I can tell, replacing one hard drive at a time will not work, as the resync is going to fail. 
RAID 1 on PERC H200 showing both hd failure predicted