This is my day job, so I'd like to weigh in.

First of all, there's a whole community of GLAM institutions involved in what is called Digital Preservation (try googling that specifically). Here in Germany, a lot of them have founded the Nestor Group (www.langzeitarchivierung.de) to further the case and share knowledge. Recently, Nestor had a discussion group on Personal Digital Archiving, addressing just your use case. They have set up a website at https://meindigitalesarchiv.de/ with the results. Nestor publishes mostly in German, but online translators are a thing, so I think you will be fine.

Some things that I want to address from your original post:

• Keep in mind that file formats, just like hardware and software, become obsolete over time. Think about a migration strategy for your files to a more recent format of your current format falls out of style and isn't as widely supported anymore. I assume your photos are JPGs, which are widely not considered safe for preservation, as they decay with subsequent encoding runs and use lossy compression. A suitable replacement might be PNG, though I wouldn't go ahead and convert my JPGs right away. For born digital photo material, uncompressed TIFF is the preferred format.
• Compression in general is considered a risk, because a damaged bit will potentially impact a larger block of compressed data. Saving a few bytes on your storage isn't worth listing your precious memories.
• Storage media have different retention times. It's true that magnetic tape storage has the best chances for survival, and it's what we use for long term cold storage, but it's prohibitively expensive for home use. Also, it's VERY slow on random access, because tape has to be rewound to the specific location of your file before reading. If you insist on using it, format your tapes using LTFS to eliminate the need for a storage management system like IBM Spectrum Protect. The next best choice of storage media are NAS grade HDDs, which will last you upwards of five years. Using redundancy and a self correcting file system like ZFS (compression & dedup OFF!) will increase your chances of survival. Keep you hands off optical storage media; they tend to decay after a year already according top studies on the subject. Flash storage isn't much greater either, avoid thumb drives at all cost. Quality SSD storage might last you a little longer. If you use ZFS or a comparable file system that provides snapshots, you can use that to implement immutability.
• Kudos for using Linux standard tooling; it will help other people understand your stack of anything happens to you. Digital Preservation is all about removing dependencies on specific formats, technologies and (importantly) people.
• Backup is not Digital Preservation, though I will admit that these two tend get mixed into one another in personal contexts. Backups save the state of a system at a specific point in time, DigiPres tries to preserve only data that isn't specific to a system and tends to change very little. Also, and that is important, DigiPres tries to save context along with the actual payload, so you might want to at least save some metadata along with your photos and store them all in a structure that is made for preservation. I recommend BagIt; there's a lot of existing tooling for creating it, it's self-contained, secured by strong checksums and it's an RFC.
• Keep complexity as low as possible!
• Last of all, good on you for doing SOMETHING. You don't have to be perfect to improve your posture, and you're on the right track, asking the right questions. Keep on going, you're doing great.

Come back at me if you have any further questions.

This is actually a real problem... A lot of digital documents from the 90's and early 2000's are lost forever. Hard drives die over time, and nobody out there has come up with a good way to permanently archive all that stuff.

I am a crazy person, so I have RAID, Ceph, and JBOD in various and sundry forms. Still, drives die.

Wherever you choose to store it, you should still consider following the 3-2-1 backup rule.

Don't use DVDs or other disc media

https://en.m.wikipedia.org/wiki/Disc_rot

I use LTO magnetic tape for archiving data, but unfortunately the tape drives are VERY expensive. The tape itself is relatively cheap though (this is a 5-pack at 12TB uncompressed, 30TB compressed per cardridge, totaling at 60TB uncompressed, 150TB compressed. This is a lot cheaper than hard drives, and lasts for much longer), has large storage capacity and 30+ years of shelf life. Yes, I know, LTO 9 has come out, but I won't be upgrading, because LTO 8 works just fine for me, and is much cheaper. The drives are backwards compatible by one generation though, e.g. you can use LTO 8 tape in an LTO 9 drive.

Assume anything you can buy has a shelf life and set a yearly reminder on your calendar to copy forward stuff more than five or so years old, if those files are of significant value to you. Or for the documents, print them out—paper has better longevity than any consumer-available electronic storage.

That being said, quality optical discs are probably the best option in terms of price to longevity ratio for the average person right now. Just keep in mind that they are not guaranteed to last forever and do need to be recopied from time to time.

(I have yet to have a DVD fail on me, but I keep them in hard plastic jewel cases in climate-controlled conditions, and I've probably just been lucky.)

Might be a dumb idea but hear me out. How about sealing a reputable enterprise or consumer SSD in one of those anti static bags with a desiccant and then sealing that inside a pvc pipe also with desiccant and then burying it below the frost line? You'll just have to dig it up and refresh everything every couple of years, think 3 years at most iirc for consumer ones. Obviously this isn't a replacement for a backup solution just archival so no interaction with it. It'll protect it from the elements, house fires, flooding, temperature fluctuations pretty much everything and its cost effective. Hell you can even surround the hard drive bag in foam then stuff in the pvc pipe for added shock absorption. Make a map afterwards like a damn pirate (its night time so my bad if I sound deranged)

edit I took a nap: in hindsight I should've clarified. I went with an ssd in this idea since its more durable than a mechanical, better price for storage capacity compared to m-disc, and most likely to be compatible with other computers in the future in case you need it for whatever reason. Of course you can use another storage media, like m disc, just know of the drawbacks. Like needing a m-disc burner (~100$), several discs depending on how big of a capacity you need (price varies), pray that there's still a drive that can read m-disc in the future and know that's its gonna be slow when getting your data back regardless. All you would have to do to modify the idea would be getting a disc case that kinda suspends the disc so nothing is touching it's surfaces. Then the same idea: antistatic bag with desiccant, foam or even bubble wrap around it, stuffed in a pipe with desiccant buried below your frost line. People usually skip the "in optimal conditions" part when talking about m-disc but this way we get close to those optimal conditions

Don't use DVDs. They suffer bitrot, as do "metal" hard drives.

You might be interested in git-annex (see the Bob use case).

It has file tracking so you can - for example - "ask" a repository at drive A where some file is, and git-annex can tell you it's on drives C and D.

git-annex can also enforce rules like: "always have at least 3 copies of file X, and any drive will do"; "have one copy of every file at the drives in my house, and have another at the drives in my parents' house"; or "if a file is really big, don't store it on certain drives".

Don’t over complicate it. 3 copies: backup, main, and offsite; 2 different media: hdd and data center; 1 offsite. I like blackblaze but anything from google to Amazon will work.

Someone else has mentioned M-Disc and I want to second that. The benefit of using a storage format like this is that the actual storage media is designed to last a long time, and it is separate from the drive mechanism. This is a very important feature - the data is safe from mechanical or electrical failure because the storage is independent of the drive. If your drive dies, you can replace it with no risk to the data. Every serious form of archival data storage is the same - the storage media is separate from the reading device.

An M-Disc drive is required to write data, but any DVD or BD drive can read the data. It should be possible to acquire a replacement DVD drive to recover the data from secondary markets (eBay) for a very long time if necessary, even after they're no longer manufactured.

3-2-1 rule with restic. Check it out.

The local-plus-remote strategy is fine for any real-world scenario. Make sure that at least one of the replicas is a one-way backup (i.e., no possibility of mirroring a deletion). That way you can increment it with zero risk.

And now for some philosophy. Your files are important, sure, but ask yourself how many times you have actually looked at them in the last year or decade. There's a good chance it's zero. Everything in the world will disappear and be forgotten, including your files and indeed you. If the worst happens and you lose it all, you will likely get over it just fine and move on. Personally, this rather obvious realization has helped me to stress less about backup strategy.

I am using https://duplicati.com/ and https://www.backblaze.com/ ( use their b2 cloud storage its variable and 6$ a month for 1TB or less depending on how much you use) run a schedule beckup every night for my photos. It's compressed and encrypted. I save a config file to my google so say if my house and server burn down. I just pull my config from google then redownload duplicati and boom pull my back up down. The whole set up backs up incremental so once you do the first back up its only changes that are uploaded. I love the whole set up.

Edit: You can also just pull files you need not the whole backup.

Use a raid atrray, and replace drives as they fail. Ideally they wouldnt fail behind your back, like an optical disk would.

As a start, follow the 3-2-1 rule:

• At least 3 copies of the data.

• On at least 2 different devices / media.

• At least 1 offsite backup.

I would add one more thing: invest in a process for verifying that your backups are working. Like a test system that is occasionally restored to from backups.

Let's say what you care about most is photos. You will want to store them locally on a computer somewhere (one copy) and offsite somewhere (second copy). So all you need to do is figure out one more local or offsite location for your third copy. Offsite is probably best but is more expensive. I would encrypt the data and then store on the cloud for my main offsite backup. This way your data is private so it doesn't matter that it is stored in someone else's server.

I am personally a fan of Borg backup because you can do incremental backups with a retention policy (like Macs' Time Machine), the archive is deduped, and the archive can be encrypted.

Consider this option:

1. Your data raw on a server/computer in your home.

2. An encrypted, deduped archive on that sane computer.

3. That archive regularly copied to a second device (ideally another medium) and synchronized to a cloud file storage system.

4. A backup restoration test process that takes the backups and shows that they restores important files, the right number, size, etc.

If disaster strikes and all your local copies are toast, this strategy ensures you don't lose important data. Regular restore testing ensures the remote copy is valid. If you have two cloyd copies, you are protected against one of the providers screwing up and removing data without you knowing and fixing it.

NAS

I would use maybe a Raspberry Pi or old laptop with two drives (preferably different brands/age, HDD or SSD doesn't really matter) in it using a checksumming filesystem like btrfs or ZFS so that you can do regular scrubs to verify data integrity.

Then, from that device, pull the data from your main system as needed (that way, the main system has no way of breaking into the backup device so won't be affected by ransomware), and once it's done, shut it off or even unplug it completely and store it securely, preferably in a metal box to avoid any magnetic fields from interfering with the drives. Plug it in and boot it up every now and then to perform a scrub to validate that the data is all still intact and repair the data as necessary and resilver a drive if one of them fails.

The unfortunate reality is most storage mediums will eventually fade out, so the best way to deal with that is an active system that can check data integrity and correct the files, and rewrite all the data once in a while to make sure the data is fresh and strong.

If you're really serious about that data, I would opt for both an HDD and an SSD, and have two of those systems at different locations. That way, if something shakes up the HDD and damages the platter, the SSD is probably fine, and if it's forgotten for a while maybe the SSD's memory cells will have faded but not the HDD. The strength is in the diversity of the mediums. Maybe burn a Blu-Ray as well just in case, it'll fade too but hopefully differently than an SSD or an HDD. The more copies, even partial copies, the more likely you can recover the entirety of the data, and you have the checksums to validate which blocks from which medium is correct. (Fun fact, people have been archiving LaserDiscs and repairing them by ripping the same movie from multiple identical discs, as they're unlikely to fade at exactly the same spots at the same time, so you can merge them all together and cross-reference them and usually get a near perfect rip of it).

I used to write to DVD's, but the failure rate was astronomical - like 50% after 5 years, some with physical separation of the silvering. Plus today they're so relatively small they're not worth using.

I've gone through many iterations and currently my home setup is this:

• I have several systems that make daily backups from various computers and save them onto a hard drive inside one of my servers.
• That server has an external hard drive attached to it controlled by a wifi plug controlled by home assistant.
• Once a month, a scheduled task wakes up that external hdd and copies the contents of the online backup directory onto it. It then turns it off again and emails me "Oi, minion. Backups complete, swap them out". That takes five minutes.
• Then I take the usb disk and put it in my safe, removing the oldest of 3 (the classic, grandfather, father, son rotation) from there and putting that back on the server for next time.
• Once a year, I turn the oldest HDD into an "Annual backup", replacing it with a new one. That stops the disks expiring from old age at the same time, and annual backups aren't usually that valuable.

Having the hdd's in the safe means that total failure/ransomware takes, at most, a month's worth. I can survive that. The safe is also fireproof and in another building to the server.

This sort of thing doesn't need to be high capacity HDDs either - USB drives and micro-SD cards are very capable now. If you're limited on physical space and don't mind slower write times (which when automating is generally ok), the microSd's and clear labelling is just as good. You're not going to kill them through excessive writes for decades.

I also have a bunch of other stuff that is not critical - media files, music. None of that is unique and can be replaced. All of that is backed to a secondary "live" directory on the same pc - mostly in case of my incompetence in deleting something I actually wanted. But none of that is essential - I think it's important to be clear about what you "must save" and what is "nice to save"

The clear thing is to sit back and work out a system that is right for you. And it always, ALWAYS should be as automated as you can make it - humans are lazy sods and easily justify not doing stuff. Computers are great and remembering to do repetitive tasks, so use that.

Include checks to ensure the backed up data is both what you expected it to be, and recoverable - so include a calendar reminder to actually /read/ from a backup drive once or twice a year.

There isn’t anything that meets your criteria.

Optical suffers from separation, hard drives break down, ssds lose their charge, tape is fantastic but has a high cost of entry.

There’s a lot of replies here, but if I were you I’d get last generation or two’s lto machine from some surplus auction and use that.

People hate being told to use magnetic tape, but it’s very reliable, long lived, pretty cost effective once you have a machine and surprisingly repairable.

What few replies are talking about is the storage conditions. If your archive can be relatively small and disconnected then you can easily meet some easy requirements for long term storage like temperature and humidity stability with a cardboard box, styrofoam cut to shape and desiccant packs (remember to rotate these!). An antifungal/antimicrobial agent on some level would be good too.

Blu-Ray USB drive and M-Discs is about the best you can get at present. Keep the drive unplugged when not in use, it'll probably last 10-20 years in storage.

Seeing as there hasn't been much advance past Blu-ray, keep an eye out for something useful to replace it in the future, or at least get another drive when you notice them becoming scarce.

I use external hard drives. Two of them, and they get rsynced every time something changes, so there's a copy if one drive should fail. Once a month, I encrypt the whole shebang with gpg and send it off into an AWS bucket.