I have recently thought about burning some data to Blu-ray and therefore looked for some cheap blank discs. To my surprise, higher density Blu-rays seem to be much more expensive than lower density ones. In my country (Germany) for example, I could buy a 25 GB BD for 0,44€. A 100 GB BD would cost me 8,77€! At that price, it would be more efficient to store 100 GB on four 25 GB discs instead of one 100 GB disc (1,76€ vs. 8,77€). Sure, if it is one file I would have to split it first and combine it again when I want to access the data, but that effort seems to be worth it.
Why are high capacity Blu-rays so much more expensive, especially compared to HDDs or SSDs where the price per GB/TB usually drops with higher capacity?
Suggesting SSD/flash for archive “cold” storage is uh, not good. SSD/flash drives are temperature sensitive, and have a lifespan of no longer than 2 years if they are not turned on periodically. For someone looking into optical storage, I’d bet a healthy wager they are looking to put some of the most important data in a closet somewhere in case of their traditional HDD setup(s) failing catastrophically. It’s not a bad idea. HDDs are also fine for “cold” storage as well, but they’re still mechanical, and having something mechanical sit there for years and turned on after a long period of time sometimes doesn’t work out well.
Any media you want to long term store, you want to rotate. Aka, move data from A, to B, to C, B to C to A, C to … Any storage media not specific designed with redundancy in mind, will see bit rot over time, depending on humidity, heat, location (if you live 2k high vs sea level), etc.
I always moved my media around like that, never had a issue with data that goes back 20 years.
For me any media is no different then having a car parked out for 6 months. Sure, it will work, but your battery may (will) be death, you brakes may get locked up, etc… Or leaving a house or apartment unattended for 6 month.
SSD for cold storage is just as good. Been using some SSDs going back to when 256GB was expensive. But like with HDDs, Tapes, etc… rotate and rewrite.
One of the biggest mistakes i have seen in a government job, was making backups, never checking / rewritting those backups and the day they needed those backups. Well, the taps had damage (despite only being 2 years cold stored). So the loads of money they spend on a dedicated guy, who’s job it was to do backups every day, the expensive tap machines, etc, was all for nothing. Simply they did not do checks/rewrites. And nobody was able to blame him, because he was following the exact instructions for making those backups. He even brought up the issue but … “instructions are made by people more qualified then you”. O, they tried to blame him but he stepped to the union and it was quickly resolved in a “nobody was to blame” (because can not blame the managers above him, now can we ;0 ). His instruction got changed to: Verify every tape at minimum X times per year, and rewrite on new taps, with backups for every tape (also increased budget to buy more tapes instead of recycling). And that was like i said, government ;)
Any storage media will fail, and its up to the end user to ensure you have regular rewrites, checks, recoverable parity of the files itself, … Say this as somebody that lost months of programming work, when his primary HDD failed and multiple backups ended up useless ( in the old floppy days ). Multiple backups helps but even that can be fraud. I have seen written DVDs go bad all at the same time (one reason i never backup to DVD or Bluray)…
So far i found SSDs more reliable then most people realize. As long as i rewrite them, every so often.
Optical discs do get bit rot, most Blu-rays are more resistant. Just keep them in a cool dry place.
What, really?!?!
pretty much, especially QLC drives or cheap flashdrives/sd cards.
Even back in the 2D TLC days, i had flash drives with read errors after less than 7 months of no power.
That explains a lot!!! Thanks
3D nand is a lot more stable unpowered, but not the cheap storage.