Re: [List] Re: zfs corruption at zroot/usr/home:<0x0>

On 14/11/2025 18:02, void wrote:
> On Fri, Nov 14, 2025 at 02:30:57PM +0100, Tomek CEDRO wrote:
>> provide backups for my clients. So far ~25 years and all CD-ROM disks
>> work fine.. and there are M-DISC DVD/BD that are advertised to last
>> 1000 years [1] but these are 25..50GB max.
>
> hi, slight correction but M-DISC have BDXL variant to 125GB now
> https://thetechylife.com/what-is-blu-ray-bdxl/
> durability up to 1000 years according to Verbatim 
> https://www.verbatim.com.au/m-disc-optical-media-benefits/
> more general M-DISC info https://mdisc.com/faq.html

MO was magnito-optical disks - they were of the 1980s and 1990s. 
Although the capacity was good, it was nothing by modern standards and 
CD/DVD overtook it in capacity and price. They were specialised, 
although the Sony MiniDisks were MO.

They had a better archive life than other technologies, which was what 
made them more interesting. I worked with a CD-R manufacturer in the 
1990s and at the time the archive life of the disks was "uncertain" to 
say the least. A lot had to do with chemistry, and the push to make the 
blank disks cheaper did nothing for the lifespan. Originally they had a 
reflective layer of gold, which is very stable over time, but rather 
pricy when cheaper reflective materials could be found!

Just to be clear, LTO is tape, not MO. It could be exactly what you're 
looking for. It's what banks use to store historic data that must be 
accessible but very rarely, and which mustn't disappear. You can get 
autoloaders (aka libraries aka jukeboxes) on places like eBay - the 
drives are interchangeable so you can upgrade them if the picker 
mechanism works.  A 2U Dell powervault holds two cartridges for 12 tapes 
each - that's 24. Let's not go crazy with the drive - say LTO8. That's 
12Tb/tape or 30Tb after the built in compression - that's 720Tb 
nearline. And if you run out just swap the tapes. I, er, have more than 
one :-)