When I was using dual-layer DVD+R blanks for off-site backups, the folk wisdom on blanks I heard from someone who burnt discs a lot was: to get a particular type and brand, and make sure the unit had been manufactured in Singapore. The country/factory of manufacture was indicated on the packaging, but the SKU and UPC didn't reflect that.
More recently, I looked into re-adding optical disks (this time, M-Disc at BD capacities) as one backup medium for current home servers, but the tech manufacturers just seemed even more user-hostile and Linux-hostile than they used to be. Maybe it's due to the intersection with piracy, maybe it's due to market forces of consumers who aren't very savvy about their own interests, but whatever the reason, it didn't look like an attractive option.
(Low-level burning software for optical drives was always crazy, and required some tricky alchemy by saintly open source programmers, as well as a user tolerance for burning the occasional "coaster" (failed burn). I layered my own, simpler, software atop their critical work. But I'm not interested in reinvesting in a category of media that in some ways seems to be getting worse, or even customer-hostile, at the same time that it's fallen out of popularity. If someone has better information, about how some corner of this is rock-solid, non-hostile, and otherwise viable, then I'd be happy to reconsider.)
I do backups of my home servers to BD-RE discs (BDXL 100GB) once a week from ZFS storage. The only problem is poor drive quality - for past five years I changed two dives (Asus branded, all different models). Seems they are not made for regular writes. So, the weak point is not the media itself but availability of dives which may just be missing in 20 years perspective.
More recently, I looked into re-adding optical disks (this time, M-Disc at BD capacities) as one backup medium for current home servers, but the tech manufacturers just seemed even more user-hostile and Linux-hostile than they used to be. Maybe it's due to the intersection with piracy, maybe it's due to market forces of consumers who aren't very savvy about their own interests, but whatever the reason, it didn't look like an attractive option.
(Low-level burning software for optical drives was always crazy, and required some tricky alchemy by saintly open source programmers, as well as a user tolerance for burning the occasional "coaster" (failed burn). I layered my own, simpler, software atop their critical work. But I'm not interested in reinvesting in a category of media that in some ways seems to be getting worse, or even customer-hostile, at the same time that it's fallen out of popularity. If someone has better information, about how some corner of this is rock-solid, non-hostile, and otherwise viable, then I'd be happy to reconsider.)