Wow, that is deep, I nodded off a third of the way down, dropped my blooming ipad.I hope your ipad wasn't harmed in any way. An interesting thing about the internet is that no matter how fringe your query, there is bound to be a small group somewhere that makes it their life's mission to delve into that topic with excruciating detail. Archiving is such a topic.
I won't go into the endless details of RAID here but I will say that unless you are ready to face a steep learning curve and a lot of stress and expense, don't implement a RAID array for yourself any more complicated than a RAID 1 mirror. It's just not worth it IMHO. Not only do you need to understand the technology, you need to understand the hardware and how to operate it. And once you venture past a simple RAID 1 mirror array, the hardware is critical for performance, acceptable reliability and even the possibility of recovery.I agree with your points about RAID 5 being inadequate for the big disks of today, and that RAID 6 has slow performance. But RAID 10 is very expensive if you don't need the performance (for 5 or more disks, say) and RAID 6 should be good enough for on-line back-up solutions. Any non-enterprise user should stay with software RAID, so understanding hardware quirks shouldn't be necessary. I thus think that RAID 6 is more often the better option for the usage pattern expected for those readers of this thread with massive backup needs. Better still would be RAID Z2, using the ZFS filesystem that protects the data against corruption through bit rot, but that is more for technically inclined.
It seems like as drive capacity/density has increased over the last few years, so has the failure rate (or at least the likelihood of data loss).I know there is the perception that this is true, but is it indeed factually true? Hard drive failures have always been an issue, with some notable examples, e.g. the IBM deskstar 75GXP (aka the "deathstar"), and more recently the Seagate 1.5TB Barracuda.
In the end, I think this about the drive quality is a bit of a red herring. Yes, you should avoid obvious duds (such as the drives mentioned above), and yes, enterprise disks have more stringent quality control. But in the long run, all drives, without exception, will fail. The trick is to plan for it, and take appropriate measures.
BUT - we are digressing. This thread is about BACKUP.While backup is indeed in the title of the thread, I think this thread is actually about data archiving:
The key difference between backup vs. archiving is that data backups are designed for the rapid recovery of operational data, while data archiving stores data that's no longer in day-to-day use but must still be retained.
I stated my thoughts above and I'll repeat that if you put your faith in writable dye based media, you better test it every year or two because there is a definite history of this type of media failing after a few years.Yes, that is why regular non-LTH blu ray discs are a much better option. Or the (more expensive) m-disc DVDs. They are not based on organic dye, so do not decay on short time scales. LTH BDs use organic dye like regular writable CDs/DVDs, so don't use them for archiving.