cultural reviewer and dabbler in stylistic premonitions

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  • 173 Comments
Joined 3 years ago
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Cake day: January 17th, 2022

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  • as i wrote in another thread:

    Content addressability is absolutely essential for building something that will last, and BlueSky gets that right. Decoupling the many responsibilities which an ActivityPub instance operator has (especially for identity) is also essential, i think, and while BlueSky’s identity solution is less than ideal it’s much better than ActivityPub and I expect it to improve.

    If you’re interested in the topic you probably want to also read the followup post from the same author (after reading the reply linked there from someone on the BlueSky team).

    Christine’s analysis is by far the best I’ve read on the topic, but I think she is too dismissive of the possibility that people will actually build things using ATP in a manner more like ActivityPub (where there doesn’t need to be a global view). It’s also possible/likely that ActivityPub will eventually evolve to adopt content addressability (Christine actually built a proof-of-concept of doing that years ago, linked in her blog post, but there doesn’t appear to be any recent progress in that direction), and decouple identity from responsibility for data availability, and adopt something like BlueSky’s composable moderation.

    Given their respective advantages over the other, i’m pretty sure that both ATP and AP will make changes which make them more like the other in the coming years.



  • Reading through it, I’m not seeing much in favor of ATP

    See the “BlueSky’s strengths” section, particularly the last paragraph of it. Content addressability is absolutely essential for building something that will last, and BlueSky gets that right. Decoupling the many responsibilities which an ActivityPub instance operator has (especially for identity) is also essential, i think, and while BlueSky’s identity solution is less than ideal it’s much better than ActivityPub and I expect it to improve.

    If you’re interested in the topic you probably want to also read the followup post from the same author (after reading the linked reply from someone on the BlueSky team).

    Christine’s analysis is by far the best I’ve read on the topic, but I think she is too dismissive of the possibility that people will actually build things using ATP in a manner more like ActivityPub (where there doesn’t need to be a global view). It’s also possible/likely that ActivityPub will eventually evolve to adopt content addressability (Christine actually built a proof-of-concept of doing that years ago, linked in her blog post, but there doesn’t appear to be any recent progress in that direction), and decouple identity from responsibility for data availability, and adopt something like BlueSky’s composable moderation.

    Given their respective advantages over the other, i’m pretty sure that both ATP and AP will make changes which make them more like the other in the coming years.

















  • (disclaimer: this information might be years out of date but i think it is still accurate?)

    SSH doesn’t have a null cipher, and if it did, using it still wouldn’t make an SSH tunnel as fast as a TCP connection because SSH has its own windowing mechanism which is actually what is slowing you down. Doing the cryptography at line speed should not be a problem on a modern CPU.

    Even though SSH tunnels on your LAN are probably faster than your internet connection (albeit slower than LAN TCP connections), SSH’s windowing overhead will also make for slower internet connections (vs rsync or something else over TCP) due to more latency exacerbating the problem. (Whenever the window is full, it is sitting there not transmitting anything…)

    So, to answer OP’s question:

    • if you want to rsync over SSH, you usually don’t need a daemon (or to specify --rsh=ssh as that is the default).
    • if you the reason you want to use the rsync daemon is performance, then you don’t want to use SSH. you’ll need to open a port for it.
    • besides performance, there are also some rsync features which are only available in “daemon mode”. if you want to use those, you have at least 3 options:
      • open a port for your rsync daemon, and don’t use SSH (bonus: you also get the performance benefit. downside, no encryption.)
      • setup an SSH tunnel and tell the rsync client it is connecting to a daemon on localhost
      • look at man rsync and read the section referred to by this:
        • The remote-shell transport is used whenever the source or destination path contains a single colon (:) separator after a host specification. Contacting an rsync daemon directly happens when the source or destination path contains a double colon (::) separator after a host specification, OR when an rsync:// URL is specified (see also the USING RSYNC-DAEMON FEATURES VIA A REMOTE-SHELL CONNECTION section for an exception to this latter rule).

    HTH.