HACKER Q&A
📣 criddell

What do you think of BDXL (100GB disks)?


I still have a need to archive data and I'm thinking about getting a BDXL writer and some disks. Is this a dumb thing to do in 2025?


  👤 solardev Accepted Answer ✓
Are you sure the physical media is suitable for archival purposes? Many discs degrade over time due to sunlight, oxidation, mechanical damages (scratches etc.) and such. I wouldn't count on them being readable in 5+ years unless the manufacturer has done accelerated aging tests and wants to vouch for their suitability.

It's also doubtful that BDXL readers are going to be available in the future. Physical discs are getting rarer and rarer.


👤 szszrk
Wow, so many weird things said so far in comments...

It is absolutely a good idea, but with some minor tweaks and for the right use case.

It's a great idea if you want to have modern hardware that is not very expensive and predictable media that will be readable after decades. And preferably a lot of pacience due to max 125GB on each disc, or low space size requirements. Discs ain't cheap, though!

For regular backups (even seldom, like half a year) I'd still go for HDDs, as they are available at around 13USD per TB. Also USB drive enclosures are as cheap as $20 so you can store them with drives. But drives will fail if you leave them with no power for a few years.

But if your archive is supposed to be one time (no often archival of the same content with minor changes), or you want to store that for many years, maybe decades, discs can be the easiest reliable way.

Standard discs won't guarantee longevity. They are sensitive to heat and moisture. Use m-discs for that. You can get them at 125GB for around $20 a piece. So MUCH more expensive than HDDs. But these will hold up for decades, don't mind humidity and even high heat.

Compatible drives are at around $100, like Verbatim I have. There are modern ones, still. With full power via USB-c, quiet, supported by popular software.

It's easy to store a drive (and even an old usff computer) in some box next to your discs, in your off-site place.

I find it more likely to be usable and better chance of being available after many years, compared to, for instance, decommissioned tape drive readers that some homelabers like to use. Also much cheaper.

Search for m-discs tests on YouTube. There are some hilarious tests there where a guy compares them with standard disks by leaving them outside during sun and rain for days, digging them in dirt, washing with soap like a plate, burning with cigarette lighter etc.

Spoiler alert: m-discs work like charm after that. Standard ones won't even spin properly.


👤 bigfatkitten
I don't trust any particular media to remain available or usable long term, either due to degradation or hardware availability. BD in particular has a very uncertain future.

I had to read a 20 year old Ultra320 HDD last weekend, and I had to dust off an old Sun workstation to do that.

I've been using LTO tape for many years, trailing a few generations for cost reasons.

Every couple of years, I read the data from my old tapes and migrate it to new tapes of the next generation, as the cost comes down.

I only have about 500GB of stuff that I particularly want to keep, mostly photographs and very short videos, along with copies of various personal documents that would be tiresome to replace. The 1.5TB provided by LTO5 is more than plenty for my own needs.


👤 tra3
Interesting question. My strategy for archival backups has been:

- local nas with decent redundancy

- a single external hard drive

- rclone everything to B2

so a lot of redundancy at relatively little cost. I have less than 100Tb but more than 20, so 100Gb would be too small..


👤 supertrope
Optical media costs more per GB/TB than hard disks. It’s lower capacity and slower so there’s more hassle swapping discs. One time use media generates trash when the data on the disc is obsolete. Discs are a better fit when the use case calls for read only access or physical copies cheap enough to literally hand out. Such as ransomware resistance or evidence chain of custody. For offline copies you could just be diligent in unplugging external hard drives and testing backups.

👤 wmf
BDXL is so expensive and low capacity. It seems totally unviable.

I thought Sony's 5.5 TB Optical Disc Archive looked cool but it was probably crazy expensive and AFAIK it's now discontinued.


👤 gus_massa
BDXL = Blu-Ray?

Aren't they discontinuing the production?


👤 summizeralert
slower so there’s more hassle swapping discs. One time use media generates trash when the data on the disc is obsolete. Discs are a better fit when the use case calls for read only access or physical copies cheap enough to literally hand out. Such as ransomware resistance or evidence chain of custody. For offline copies you could just be diligent in unplugging external hard drives and testing backups. reply

👤 pickle-wizard
I would think that tape would be better for archival storage. My experience has been that the writeable optical media does not hold up well long term.

👤 brudgers
I think my age gives me a romantic attraction to the idea of BDXL. Engineering brain says "most likely, no."

Per GB, spinning rust is faster, cheaper, more mature, physically smaller, less fiddly, easier to obtain from Walmart at 10pm Tuesday night, and doesn't require special hardware made by a handful of manufacturers only in a short window of time.

As a small-run distribution medium, BDXL might be the right technology.

All with the caveat that BDXL might be an improvement over an existing archive practice. For clarity not archiving is not an existing archive practice and BDXL is not going to transform anyone into the kind of person who systematically archives their work...

...you will use BDXL as much as you used floppies, CDR, Zip, etc. Good luck.