Probably one of the main design objectives behind RAID/md
md is 100% guaranteed perfect or your money back...
rsync is 100% guaranteed perfect or your money back...
your backups are 100% guaranteed perfect or your money back...
your hard drives are 100% guaranteed perfect or your money back...
your CPU and RAM are 100% guaranteed perfect or your money back...
your CPU and PSU fans are 100% guaranteed perfect or your money back...
Clearly if you want to panic over reliability you have lots of choices :)
David
PS, FWIW md has saved my data* countless times over the past 'n' years in
exactly the scenario you describe.
*(or more accurately has saved me from having to restore my data)
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