So far from what I have seen, 8TB drives in general have had a lot of issues. Over 30% of the ones that have either come into my shop for recovery or we have bought has had some kind of issue.
Though mostly the WD helium drives.
Running a RAID 5 with a battery is a must personally. Then again, if you are running ZFS like I do then it doesn't matter. Just need a HBA.
Nothing like a self-healing redundent file system with built in snapshots.
I would HIGHLY recommend you maintain a backup bud. The moment you plug in that replacement drive and rebuild your array, you could be setting yourself up for a world of hurt. The rebuild process is tough on drives so another could fail. RAID 5 w/ 2 failed disks is bad news (and occasionally extremely difficult to recover from).
Okay, this one is interesting but not my case directly.
My cohort in crime (lets call him Jim) recently had a WD drive (Sadle G6) come in with something very interesting: Massive firmware failure. I mean, it was bad.
No matter what we could do, the drive would not get ready correctly, however, after doing a hot swap we did have access to its modules and tracks. Now, how did you deal with a drive with horrible firmware issues? One solution is called a Smart Hot...
You need another computer. You could also use a LiveCD of Ubuntu or something.
If you still cannot access the drive even from another computer, then you COULD use software, however, at that point recovery may be more difficult. This may result in you having to send it out to a data recovery company.
Please bare in mind you are going to have to replace your hard drive.
Also check out this thread it may...