gouldopfl wrote:
I wouldn't trust either CD's or DVD's in the long run. They degrade just like a disk drive. I have a home NAS of 9 drives, 5 with 8 TB and 4 1 tb SSD drives for cache and using QTier a Qnap product. All are enterprise drives. I still keep cold storage on Amazon AWS which is pretty cheap. Running raid 10 on my NAS ensures that I can rebuild any one disk upon failure. Any drive can fail. Having cold storage at Amazon is about as safe as it gets.
Everything has a chance of failure. M-disc claims a much longer shelf life (for media) than hard drives. That doesn't make them infallible either.
Load up 40 x 100GB m-discs and load up a 4GB drive with the same data. The disc bring a few advantages. Even if you have to plug in an external reader with a USB cable, it's still quicker than installing a bare HD. (Sure, you can pay extra to store your drive in an enclosure, but that's a waste for an archival drive.)
Also, if a disc goes bad you still have 3.9 TB of saved data. That 4TB drive goes down and it's game over for all the data.
The HD is also a mechanical device with more to possibly go wrong. A disc has no moving parts to wear out or break. If your optical disc drive fails, you data is still secure and can be read in any other optical drive.
I am also running a QNAP NAS. It's great when it works. I have 4x10TB enterprise drives in a RAID 10 configuration. Two of the four drives have failed in the first year. A third one looks like it will fail in the next few months. Aside from the security of RAID, all that data is also backed up to other devices (including optical).
The real answer is to use more than one media for long term storage. A hard drive is great, so is optical. If you really want the "best" go with tape. Each has its plus and minus. There is no perfect solution.
I have looked at cloud services and they are not practical for me. Two services have already told me "don't bother" because it isn't practical to upload 10+TB of data. I went a different "cloud" route. I have a second NAS setup at an offsite location. Initial sync was done on a local connection, then the box moved offsite. Now I only have to worry about incremental updates.
Of course, 2 of those drives have also failed in the past 3 years. All replaced under warranty, but I am still very skeptical of hard drives, enterprise or otherwise.