Hmm but you should be having your RAID system perform:
* verification (checking a read to all copies and CRC validates correctly as expected)
* scrubbing (writing some other random patterns to each block of the disk, to confirm the disk is in good order, and will take new data, it also re-energises the disk, the original data is then written back into the block, and then verified, before it moves on to another part of the disk, this operation often requires battery backed memory, since the original data is preserved robustly this way over unwanted power outage).
Ideally you should verify (the whole storage) at least once per week, and scrub (the whole storage) once per month. These operations with hardware cards can be performed slowly in the background, but often a few hours a day during offpeak will do the job.
Doing this alone can extend the life of disks, compared to writing some block of data, no accessing it for 5 years, then wondering why in 5 years time the block is no corrupted.
Both these operations provide a better health check of RAID than SMART along, since SMART only knows of a problem after it saw a problem, and that often requires you to access the problem area of disk. This is what verification/scrubbing does on your behalf continuously over a week.