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On Sun, 14 Aug 2022 19:03:25 -0400, |
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Rich Freeman wrote: |
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> |
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> On Sun, Aug 14, 2022 at 6:44 PM Dale <rdalek1967@×××××.com> wrote: |
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> > |
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> > Right now, I'm using rsync which doesn't compress files but does just |
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> > update things that have changed. I'd like to find some way, software |
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> > but maybe there is already a tool I'm unaware of, to compress data and |
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> > work a lot like rsync otherwise. |
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> |
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> So, how important is it that it work exactly like rsync? |
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> |
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> I use duplicity, in part because I've been using it forever. Restic |
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> seems to be a similar program most are using these days which I |
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> haven't looked at super-closely but I'd look at that first if starting |
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> out. |
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> |
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> Duplicity uses librsync, so it backs up exactly the same data as rsync |
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> would, except instead of replicating entire files, it creates streams |
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> of data more like something like tar. So if you back up a million |
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> small files you might get out 1-3 big files. It can compress and |
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> encrypt the data as you wish. The downside is that you don't end up |
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> with something that looks like your original files - you have to run |
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> the restore process to extract them all back out. It is extremely |
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> space-efficient though - if 1 byte changes in the middle of a 10GB |
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> file you'll end up just backing up maybe a kilobyte or so (whatever |
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> the block size is), which is just like rsync. |
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> |
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> Typically you rely on metadata to find files that change which is |
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> fast, but I'm guessing you can tell these programs to do a deep scan |
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> which of course requires reading the entire contents, and that will |
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> discover anything that was modified without changing ctime/mtime. |
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> |
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> The output files can be split to any size, and the index info (the |
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> metadata) is separate from the raw data. If you're storing to |
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> offline/remote/cloud/whatever storage typically you keep the metadata |
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> cached locally to speed retrieval and to figure out what files have |
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> changed for incrementals. However, if the local cache isn't there |
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> then it will fetch just the indexes from wherever it is stored |
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> (they're small). |
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> |
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> It has support for many cloud services - I store mine to AWS S3. |
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> |
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> There are also some options that are a little closer to rsync like |
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> rsnapshot and burp. Those don't store compressed (unless there is an |
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> option for that or something), but they do let you rotate through |
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> multiple backups and they'll set up hard links/etc so that they are |
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> de-duplicated. Of course hard links are at the file level so if 1 |
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> byte inside a file changes you'll end up with two full copies. It |
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> will still only transfer a single block so the bandwidth requirements |
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> are similar to rsync. |
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|
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I have been using restic for a while, and although it does not do |
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compression, there are a couple of nice things it does -- if a file is |
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in more than one location, or if you rename the file, its smart enough |
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not to backup any data at all, just the metadata. Also, you never |
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have to delete the whole backup and start over like you have to do |
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with duplicity, you can just delete backups older than a certain |
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number of days and you are good to go. Its in go, so building can be |
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a pain and I don't like programs which download gobs of stuff from the |
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internet to build, but it seems to work quite well. |
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|
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-- |
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Your life is like a penny. You're going to lose it. The question is: |
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How do |
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you spend it? |
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|
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John Covici wb2una |
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covici@××××××××××.com |