All drives today still need backup copies. If you left your backup to the day when something failed then you are going to possibly lose some files.
Since you are on a Apple computer my other ideas on copy software may not apply so your next move may be to get an estimate from Drivesavers.com
RAID is not backup. I've seen folk try to use RAID 1 as backup and it fails leaving them in a fit. Same story here. Don't rely on a single system.
I had a two disk RAID 1 that was acting odd. I thought it had died, and was advised it was by the manufacturer's tech support. I backed up the data and ordered a new enclosure from a different vendor. I loaded formatted drives to the new enclosure. Whenever I copy files to it, the raid crashes and disconnects.
In single mode, where both the drives in the enclosure show up as individual drives, things copy just fine. So I thought the enclosure had bad RAID hardware parts. To verify, I loaded two different drives into the RAID, and things seem to be copying just fine.
What is happening? Is it possible that one of the original drives is damaged just enough to make it perform poorly, making the RAID crash? I've been trying to eliminate as many variables as possible. I know that the issue is not corrupt files since there have been crashes as RAID with multiple different copy sources, while successful copies from the same sources as a generic transfer. I have run a disk utility first aid on all the individual drives and all verified as OK. Since this is connected to a Mac, support suggested I install SMART drivers, which I did with no change.
Any help would be greatly appreciated.
Cheers

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