traches

Try it out. Order coffee with it

Broadly similar from a quick glance: https://www.amazon.pl/s?k=m-disc+blu+ray

My options look like this:

https://allegro.pl/kategoria/nosniki-blu-ray-257291?m-disc=tak

Exchange rate is 3.76 PLN to 1 USD, which is actually the best I’ve seen in years

I only looked how zfs tracks checksums because of your suggestion! Hashing 2TB will take a minute, would be nice to avoid.

Nushell is neat, I’m using it as my login shell. Good for this kind of data-wrangling but also a pre-1.0 moving target.

Tailscale deserves it, bitcoin absolutely does not

Where I live (not the US) I’m seeing closer to $240 per TB for M-disc. My whole archive is just a bit over 2TB, though I’m also including exported jpgs in case I can’t get a working copy of darktable that can render my edits. It’s set to save xmp sidecars on edit so I don’t bother with backing up the database.

I mostly wanted a tool to divide up the images into disk-sized chunks, and to automatically track changes to existing files, such as sidecar edits or new photos. I’m now seeing I can do both of those and still get files directly on the disk, so that’s what I’ll be doing.

I’d be careful with using SSDs for long term, offline storage. I hear they lose data if not powered for a long time. IMO metadata is small enough to just save a new copy when it changes

I’ve been thinking through how I’d write this. With so many files it’s probably worth using sqlite, and then I can match them up by joining on the hash. Deletions and new files can be found with different join conditions. I found a tool called ‘hashdeep’ that can checksum everything, though for incremental runs I’ll probably skip hashing if the size, times, and filename haven’t changed. I’m thinking nushell for the plumbing? It runs everywhere, though they have breaking changes frequently. Maybe rust?

ZFS checksums are done at the block level, and after compression and encryption. I don’t think they’re meant for this purpose.

Aww, man, I’m conflicted here. On one hand, I’ve enjoyed their work for years and they seem like good dudes who deserve to eat. On the other, they’re AI enthusiast crypto-bros and that’s just fucking exhausting. I deal with enough of that bullshit at work

Edit: rephrase for clarity

humans are neat

I know lemmy is social media for people with a favorite Linux distro so I’m preaching to the choir here, but so much software is free as in speech it is truly wonderful. It’s like the only thing I love about being a millennial

Yeah, you're probably right. I already bought all the stuff, though. This project is halfway vibes based; something about spinning rust just feels fragile you know?

I'm definitely moving away from the complex archive split & merge solution. fpart can make lists of files that add up to a given size, and fd can find files modified since a given date. Little bit of plumbing and I've got incremental backups that show up as plain files & folders on a disk.

Ohhh boy, after so many people are suggesting I do simple files directly on the disks I went back and rethought some things. I think I'm landing on a solution that does everything and doesn't require me to manually manage all these files:

• fd (and any number of other programs) can produce lists of files that have been modified since a given date.
• fpart can produce lists of files that add up to a given size.
• xorrisofs can accept lists of files to add to an iso

So if I fd a list of new files (or don't for the first backup), pipe them into fpart to chunk them up, and then pass these lists into xorrisofs to create ISOs, I've solved almost every problem.

• The disks have plain files and folders on them, no special software is needed to read them. My wife could connect a drive, pop the disk in, and the photos would be right there organized by folder.
• Incremental updates can be accomplished by keeping track of whenever the last backup was.
• The fpart lists are also a greppable index; I can use them to find particular files easily.
• Corruption only affects that particular file, not the whole archive.
• A full restore can be accomplished with rsync or other basic tools.

Downsides:

• Change detection is naive. Just mtime. Good enough?
• Renames will still produce new copies. Solution: don't rename files. They're organized well enough, stop messing with it.
• Deletions will be disregarded. I could solve this with some sort of indexing scheme, but I don't think I care enough to bother.
• There isn't much rhyme or reason to how fpart splits up files. The first backup will be a bit chaotic. I don't think I really care.
• If I rsync -a some files into the dataset, which have mtimes older than the last backup, they won't get slurped up in the next one. Can be solved by checking that all files are already in the existing fpart indices, or by just not doing that.

Honestly those downsides look quite tolerable given the benefits. Is there some software that will produce and track a checksum database?

Off to do some testing to make sure these things work like I think they do!