I don’t think this meets the definition of 3-2-1. Which isn’t a problem if it meets your requirements. Hell, I do something similar for my stuff. I have my primary NAS backed up to a secondary NAS. Both have BTRFS snapshots enabled, but the secondary has a longer retention period for snapshots. (One month vs one week). Then I have my secondary NAS mirrored to a NAS at my friends house for an offsite backup.

This is more of a 4-1-1 format.

But 3-2-1 is supposed to be:

• Three total copies of the data. Snapshots don’t count here, but the live data does.

• On two different types of media. I.e. one backup on HDD and another on optical media or tape.

• With at least one backup stored off site.

There are a few optical storage mediums designed for long term archival storage. Like M-Disc or (as mentioned in the article) pioneers DM for Archive, both of which are still commercially available.

And provided they’re stored properly, even more general consumer oriented optical media can easily last a few decades. Granted the environmental aspect of “proper storage” (<50% relative humidity, constant temp <80F and >50F) can be difficult to achieve at home in a lot of regions, but generally banks and credit unions have an option to get a safety deposit box which is generally in an environmentally controlled room. Other than that just store your media in an opaque single disc case.

Take the power back - Rage Against the Machine

Yes. The flame is a cloud of gas and particulate heated to the point that it glows. It will reflect light. Just not a lot, and it’s also emitting enough light to overpower any reflected light in most conditions.

And of course the candle itself reflects light.

But they still do. It might just be overpowered by the emitted light.

Is there a link to the code? I know I could probably search for it, but if you’re going post about the code being public you could at least include a link to it.