I’m in the process of starting a proper backup solution however over the years I’ve had a few copy-paste home directory from different systems as a quick and dirty solution. Now I have to pay my technical debt and remove the duplicates. I’m looking for a deduplication tool.

  • accept a destination directory
  • source locations should be deleted after the operation
  • if files content is the same then delete the redundant copy
  • if files content is different, move and change the name to avoid name collision I tried doing it in nautilus but it does not look at the files content, only the file name. Eg if two photos have the same content but different name then it will also create a redundant copy.

Edit: Some comments suggested using btrfs’ feature duperemove. This will replace the same file content with points to the same location. This is not what I intend, I intend to remove the redundant files completely.

Edit 2: Another quite cool solution is to use hardlinks. It will replace all occurances of the same data with a hardlink. Then the redundant directories can be traversed and whatever is a link can be deleted. The remaining files will be unique. I’m not going for this myself as I don’t trust my self to write a bug free implementation.

  • geoma@lemmy.ml
    1·
    6 months ago

    What about folders? Because sometimes when you have duplicated folders (sometimes with a lot of nested subfolders), a file deduplicator will take forever. Do you know of a software that works with duplicate folders?

    • Agility0971@lemmy.worldOP
      1·
      6 months ago

      What do you mean that a file deduplication will take forever if there are duplicated directories? That the scan will take forever or that manual confirmation will take forever?

  • HumanPerson@sh.itjust.worksEnglish
    1·
    6 months ago

    I believe zfs has deduplication built in if you want a separate backup partition. Not sure about its reliability though. Personally I just have a script that keeps a backup and an oldbackup, and they are both fairly small. I keep a file in my home dir called excluded for things like linux ISOs that don’t need backed up.

  • biribiri11@lemmy.ml
    21·
    6 months ago

    As said previously, Borg is a full dedplicating incremental archiver complete with compression. You can use relative paths temporarily to build up your backups and a full backup history, then use something like pika to browse the archives to ensure a complete history.

      • biribiri11@lemmy.ml
        2·
        6 months ago

        Tbf you did start your post with

        I’m in the process of starting a proper backup

        So you’re going to end up with at least a few people talking about how to onboard your existing backups into a proper backup solution (like borg). Your bullet points can certainly probably be organized into a shell script with sync, but why? A proper backup solution with a full backup history is going to be way more useful than dumping all your files into a directory and renaming in case something clobbers. I don’t see the point in doing anything other than tarring your old backups and using borg import-tar (docs). It feels like you’re trying to go from one half-baked, odd backup solution to another, instead of just going with a full, complete solution.

  • utopiah@lemmy.ml
    11·
    6 months ago

    I don’t actually know but I bet that’s relatively costly so I would at least try to be mindful of efficiency, e.g

    • use find to start only with large files, e.g > 1Gb (depends on your own threshold)
    • look for a “cheap” way to find duplicates, e.g exact same size (far from perfect yet I bet is sufficient is most cases)

    then after trying a couple of times

    • find a “better” way to avoid duplicates, e.g SHA1 (quite expensive)
    • lower the threshold to include more files, e.g >.1Gb

    and possibly heuristics e.g

    • directories where all filenames are identical, maybe based on locate/updatedb that is most likely already indexing your entire filesystems

    Why do I suggest all this rather than a tool? Because I be a lot of decisions have to be manually made.

    • utopiah@lemmy.ml
      1·
      6 months ago

      if you use rmlint as others suggested here is how to check for path of dupes

      jq -c '.[] | select(.type == "duplicate_file").path' rmlint.json

    • utopiah@lemmy.ml
      1·
      6 months ago

      FWIW just did a quick test with rmlint and I would definitely not trust an automated tool to remove on my filesystem, as a user. If it’s for a proper data filesystem, basically a database, sure, but otherwise there are plenty of legitimate duplication, e.g ./node_modules, so the risk of breaking things is relatively high. IMHO it’s better to learn why there are duplicates on case by case basis but again I don’t know your specific use case so maybe it’d fit.

      PS: I imagine it’d be good for a content library, e.g ebooks, ROMs, movies, etc.