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Replication is not a backup as was already mentioned. A great example of this is when the KDE project almost lost all of their Git repos because they were mirro

Replication is not a backup as was already mentioned. A great example of this is when the KDE project almost lost all of their Git repos because they were mirroring a corrupted copy of the data. https://www.phoronix.com/scan.php?page=news_item&px=MTMzNTc https://www.phoronix.com/scan.php?page=news_item&px=MTMzNTc

Eikon 7y ago
A backup is a replication of the live dataset, although, usually out of sync to be useful when the main dataset goes bad.
- y4mi 7y ago
  You might want to read the Wikipedia definition, because you're technically mistaken. https://en.m.wikipedia.org/wiki/Backup https://en.m.wikipedia.org/wiki/Backup
  - Eikon 7y ago
    I'm not, you can't do backup without replicating data, hence, if you do backup, you are doing replication.
    - y4mi 7y ago
      It can be, it just doesn't have to be Let's say a typical admin of a small shop wants to backup his postgres database. The first thing he'll use is probably pg_dumpall which he'll output to a storage. No replication involved. The backup is just a bunch of sql statements to recover the last known state of the database. It's a different kind of format however, which -by definition- isn't a replica anymore. (And this process has several caveat's-one of which is that it can produce unusable dumps in some rare cases and isn't complete. users, triggers etc aren't dumped iirc.. could be wrong there)
      - Eikon 7y ago
        > No replication involved. The backup is just a bunch of sql statements to recover the last known state of the database. You probably should look up the definition of “replication”.
        deleted 7y ago
        [deleted]
        deleted 7y ago
        [deleted]
      - ben509 7y ago
        > It's a different kind of format however, which -by definition- isn't a replica anymore. All non-trivial replication has to cross machine boundaries. To transmit to another machine, you have to use a serial format since there are no pointers on the wire. So insisting that a replica must be the same format prohibits the concept of replication in practice.
        y4mi 7y ago
        So, that admin dumped his database but didn't know that the data was using a custom locale which makes recovery troublesome. How is it a copy if it can't recover the original in some cases? We're not talking about a compressed archive here, it's a (incomplete) step-by-step instruction to recreate the data. If anything out of norm happens, it's gonna fail-possibly silently.
        ben509 7y ago
        > How is it a copy if it can't recover the original in some cases? Do you think a gun is not a gun if it sometimes jams? > We're not talking about a compressed archive here I think we have two camps. Mine is considering "copy", "backup", "replica" to be broad categories that are distinguished by simple mathematical or technical properties. For instance, I'd consider a device that copied a single bit to be "copying," even though it's arguably just a wire. The other camp has very specific products and tasks in mind. A replica is associated with distributed computing, while a backup is something a systems administrator makes as part of disaster recovery.
  - ben509 7y ago
    That's a long article; please quote the part you're referring to so we're all looking at the same text. > a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event Since a "replica" is a copy, that seems technically correct.
    - y4mi 7y ago
      all fruits are apples because apples are fruit, right?
      - ben509 7y ago
        Your definition claims "a backup is a copy." The original claim was "a backup is a replication of the live dataset, although, usually out of sync to be useful when the main dataset goes bad." The only thing that makes a replica special is that it's in sync. Once you add the caveat that it's out of sync, it's just a copy.
        deleted 7y ago
        [deleted]
- Ma8ee 7y ago
  The out of sync part is rather important when something accidently get deleted from the live dataset.
CydeWeys 7y ago
Fortunately, git is a DVCS, so anyone who checks out a repo has a complete copy of it. Now, granted, it'd be a huge pain to track down all the people who had copies of the 1,500 different repos, and try to find as up-to-date as possible of a version of each, but I doubt they got anywhere close to potentially losing all their source code. Incidentally this shows why it's a good idea to sync your repo to GitHub, even if the canonical repo is elsewhere: in addition to the usual reasons of incentivizing some contributors by giving them "GitHub credit", and increasing visibility of your project's code, GitHub can serve as a backup! Also, on a side-note, 1,500 separate repositories?! That sounds way overkill. I wonder if they'd benefit from having a monorepo.
- rjmunro 7y ago
  > 1,500 separate repositories?! That sounds way overkill. I wonder if they'd benefit from having a monorepo. No it doesn't. Github has at least 20 million public repositories. Would they benefit by combining them into a monorepo?
  - gdxhyrd 7y ago
    GP is talking about the KDE project, not the entirety of GitHub. And yes, a monorepo is usually the best approach in most cases for a project or even an entire company.

Eikon 7y ago

A backup is a replication of the live dataset, although, usually out of sync to be useful when the main dataset goes bad.

y4mi 7y ago
You might want to read the Wikipedia definition, because you're technically mistaken. https://en.m.wikipedia.org/wiki/Backup https://en.m.wikipedia.org/wiki/Backup
- Eikon 7y ago
  I'm not, you can't do backup without replicating data, hence, if you do backup, you are doing replication.
  - y4mi 7y ago
    It can be, it just doesn't have to be Let's say a typical admin of a small shop wants to backup his postgres database. The first thing he'll use is probably pg_dumpall which he'll output to a storage. No replication involved. The backup is just a bunch of sql statements to recover the last known state of the database. It's a different kind of format however, which -by definition- isn't a replica anymore. (And this process has several caveat's-one of which is that it can produce unusable dumps in some rare cases and isn't complete. users, triggers etc aren't dumped iirc.. could be wrong there)
    - Eikon 7y ago
      > No replication involved. The backup is just a bunch of sql statements to recover the last known state of the database. You probably should look up the definition of “replication”.
      - deleted 7y ago
        [deleted]
      - deleted 7y ago
        [deleted]
    - ben509 7y ago
      > It's a different kind of format however, which -by definition- isn't a replica anymore. All non-trivial replication has to cross machine boundaries. To transmit to another machine, you have to use a serial format since there are no pointers on the wire. So insisting that a replica must be the same format prohibits the concept of replication in practice.
      - y4mi 7y ago
        So, that admin dumped his database but didn't know that the data was using a custom locale which makes recovery troublesome. How is it a copy if it can't recover the original in some cases? We're not talking about a compressed archive here, it's a (incomplete) step-by-step instruction to recreate the data. If anything out of norm happens, it's gonna fail-possibly silently.
        ben509 7y ago
        > How is it a copy if it can't recover the original in some cases? Do you think a gun is not a gun if it sometimes jams? > We're not talking about a compressed archive here I think we have two camps. Mine is considering "copy", "backup", "replica" to be broad categories that are distinguished by simple mathematical or technical properties. For instance, I'd consider a device that copied a single bit to be "copying," even though it's arguably just a wire. The other camp has very specific products and tasks in mind. A replica is associated with distributed computing, while a backup is something a systems administrator makes as part of disaster recovery.
- ben509 7y ago
  That's a long article; please quote the part you're referring to so we're all looking at the same text. > a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event Since a "replica" is a copy, that seems technically correct.
  - y4mi 7y ago
    all fruits are apples because apples are fruit, right?
    - ben509 7y ago
      Your definition claims "a backup is a copy." The original claim was "a backup is a replication of the live dataset, although, usually out of sync to be useful when the main dataset goes bad." The only thing that makes a replica special is that it's in sync. Once you add the caveat that it's out of sync, it's just a copy.
      - deleted 7y ago
        [deleted]
Ma8ee 7y ago
The out of sync part is rather important when something accidently get deleted from the live dataset.

CydeWeys 7y ago

Fortunately, git is a DVCS, so anyone who checks out a repo has a complete copy of it. Now, granted, it'd be a huge pain to track down all the people who had copies of the 1,500 different repos, and try to find as up-to-date as possible of a version of each, but I doubt they got anywhere close to potentially losing all their source code. Incidentally this shows why it's a good idea to sync your repo to GitHub, even if the canonical repo is elsewhere: in addition to the usual reasons of incentivizing some contributors by giving them "GitHub credit", and increasing visibility of your project's code, GitHub can serve as a backup! Also, on a side-note, 1,500 separate repositories?! That sounds way overkill. I wonder if they'd benefit from having a monorepo.

rjmunro 7y ago
> 1,500 separate repositories?! That sounds way overkill. I wonder if they'd benefit from having a monorepo. No it doesn't. Github has at least 20 million public repositories. Would they benefit by combining them into a monorepo?
- gdxhyrd 7y ago
  GP is talking about the KDE project, not the entirety of GitHub. And yes, a monorepo is usually the best approach in most cases for a project or even an entire company.