greaber

Syq has compression turned on by default. Also, if you are updating a file that already exists on the other end, syq will only send blocks of the file that changed.

Also, in syq, a connection is the unit of independent transfer work. Probably it would be possible to get higher bandwidth per TCP connection by some kind of multiplexing, but that architecture would be more complex and probably not have many benefits.

They are benchmarks on real hardware, and I tried to provide enough details so that anyone can reproduce them (but some of the benchmarks are on servers I have that you can't order on public cloud -- these ones are clearly marked). "Synthetic" means that the data is synthetic, not an actual production workload. For instance, some of the benchmarks use files filled with random bytes.

Nice example. Rsync might be better here. Although syq will still avoid copying most of the image if changing the config file just modifies a small number of locations and doesn't globally move data around (like prepending a single byte to the ISO)

Yeah, I kind of regret writing "better than rsync" in the tagline. Maybe I should have written "better than rsync in some respects".

Yeah, I get that. I really didn't mean to sound conceited, and I don't think that syq is better than rsync for every use case. I was just trying to convey in a very short space that it is something that rsync users might be interested in because it solves some frustrations with rsync.

Thanks! Yeah, I was a little surprised (maybe I shouldn't have been) at how negative some of the comments were. I will think about what additional explanations I can provide that will help people. Regarding rclone, I have also spent a bunch of time looking at faster transfers to and from S3-compatible storage, but that problem is somewhat different, and I didn't look in depth at how rclone is implemented. FWIW, in my experience, s5cmd is generally a bit faster than rclone even if you tune rclone options. (But rclone is more flexible.) My guess is that s5cmd is already close to the performance ceiling, but I don't really know.

As for edge cases, I will also try to document that more. In general, when I'm not sure what semantics to go for, I try to either copy what rsync does or do something safer. For instance, one thing I am looking at now is the best way to handle cases where a source path cannot be represented on the target filesystem or where two source paths would collide (e.g. due to unicode normalization or case insensitivity). Tentatively, my inclination is to try to fail before copying any files when possible. Currently, syq doesn't do this (but neither does rsync).

I entirely agree that multiple connections shouldn't actually be necessary for speed, but they help in multiple situations (long-distance transfers, same DC between servers, NFS), and it's not just about amortizing per-file setup overhead.

There is some info on the optimizations in the docs, but I agree that a more complete technical explanation of all the things syq does could be useful. I will work on one. On the other hand, I also tried hard to make it just go fast without needing the user to understand why it is fast or tune anything. For instance, the number of connections is auto-tuned by default.

Yeah, ControlMaster is cool and was an inspiration, but since the syq client is always talking to the same receiver on the server, we can save a few round trips that ControlMaster still needs, so syq persist feels faster. This architecture is also what enables reverse mode, where you can download to your laptop while working on the server.

ProxyJump doesn't help when you want to copy files from server A to server B without giving server A an agent that can do arbitrary things on server B. There is really no alternative to using a restricted authorized key on server B for this scenario.

It just installs in $HOME/.local/bin by default (and some other parts go in other locations inside your home directory). You don't need superuser access for anything. The first time you connect to a server, it installs its matching counterpart in your home directory on the server.

Thanks for the suggestion! I'm not very familiar with btrfs send and btrfs receive. Browsing the documentation, it looks cool, but maybe you could say more about the specific things that make it so much better for your use case? Could any of them be incorporated into a more general tool like syq? Also, it doesn't look like btrfs send helps transfers go fast by parallelizing them or has anything like syq's remote-remote transfer feature, which made me wonder if it would actually make sense to make syq able to work as an authenticated fast transport for a stream generated by btrfs send/receive.