I was getting these errors for the first time ever, but nowhere near as bad as yours. Mine was spitting out 1 or 2 a week, and only on certain drives. In my case, it ended up being a defective SFF-8087 to breakout 4xSATA cable that I had. Replaced it and it's been three months, not a single one since.
Given that you have 8 drives that are spitting out errors, I truly hope that it isn't an HBA card that has gone bad. If you have a spare HBA or data cables, I'd swap and see if that alleviates the issue.
Thankfully those errors *shouldn't* cause any data corruption issues, from what I've seen (checksums for random files on my drives came back fine,) however, I've had a total of 14 errors on the 4 drives on the cable, which you've obviously had a lot more of.
Good luck.