> I also added cool features like the ability to maintain a persistent ssh connection to the server for fast one-offs
rsync already supports this via OpenSSH's ControlMaster directive. Bonus, it speeds up every connection to that server rather then a single tool's.
> the ability to do direct remote-remote transfers without forwarding your ssh agent (by using restricted ssh keys on the receiver that will only execute a specific request signed with the key on your laptop).
You can control your agent forwarding in your local ssh client configuration. And with modern ProxyJump, you don't need to forward your agent at all regardless of how many bastion hops are between you and your final target.
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.
I thought I'd share a more positive comment. I work on a tool in a similar area (moving stuff around) but on a higher level. I currently use rsync or rclone for the file moving parts. So to me your tool looks interesting and promising, thanks for sharing it :)
Some suggestions for improvement for your website/Github:
- I wanted to understand how it differs from rsync. A comparison page would be helpful.
- A comparison to rclone would also be interesting, as it also uses multiple parallel connections.
- As it target more advanced users I think it would be helpful to provide more advanced technical insights on how your transfers exactly work. Also how are edge cases handled, what tests are done? Moving and copying files is critical, and you need to inspire trust in your project among users.
Thank you for showing this. I'll echo what some others say: if you're claiming to be faster than rsync, you should demonstrate why front-and-center. There have been decades of documentation on how rsync optimizes transfers, so it's a lot to live up to.
As an aside, It's perhaps an indictment of our networking landscape that multiple parallel connections between 2 specific machines would accelerate a transfer. I would've expected a single TCP connection to be able to saturate a line. Or perhaps the parallel connections seeks to amortize the per-file setup overhead?
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 had 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.
Currently, there is just a fixed range of ports that it will use if they are open and you don't pass `--no-tcp`. It does its own encryption over the TCP connections. Also worth knowing is that for some connections (e.g. if there are any dropped packets), you may get much better performance if you can enable BBR congestion control. https://greaber.github.io/syq/server-tuning.html#test-conges...
Browsing the repo, I can see a couple of advantages:
- Single contributor. Software bugs are generally caused by developers writing code. By reducing the number of contributors, syq has cleverly reduced the surface area for defects to sneak in.
- Distribution via shell script. rsync is bundled in most linux distributions, which means you have to deal with annoying software updates from time to time. Syq, OTOH, tells you to pipe curl into bash to execute a shell script, which means one-and-done installation and maintenance.
- UI clarity. If you search StackOverflow for rsync, you'll see thousands of questions asking how to accomplish various tasks with rsync, both straightforward and arcane. By contrast, `syq` isn't even a tag on SO. The obvious conclusion here is that rsync's interface is so byzantine, and its documentation so poor, that users must resort to asking strangers for help, a problem obviously not shared by syq.
- No need to be snarky. It's a new project, while rsync is time tested, and that is certainly an advantage for rsync and all old software.
- You can install by piping curl to bash, using brew, or by compiling yourself. One thing about distribution I would argue syq gets right is that you are never relying on whatever version of syq happens to be installed on a server. The client syq always talks to a server syq tagged with the exact same version, and when your local copy of syq installs a remote copy, it verifies that the remote binary is signed by me.
- I never said or implied that rsync has a byzantine interface or poor documentation. I think rsync is well documented and the interface is overall fine. Syq even has an rsync compatibility mode, so you don't have to learn any new syntax if you don't want. Still, I tried to provide good docs for syq too, and honestly even if there were a gap in the docs, all you have to do these days is ask AI to look at the source code and tell you what to do. I think this also mitigates the trust issue with a new project from a single contributor.
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.
There are a bunch of reasons, some of which are explained in the description and in the docs. For me, the most important benefit is speed of copying. Note that syq doesn't currently implement rsync's delta merge algorithm, which allows it to avoid copying data that is already in the destination file but at a shifted offset. I might implement this (or an enhanced version of it) in the future. If your workloads have a lot of cases like this then syq might not be better than rsync for you, but I found that for me this rarely came up.
One instance where rsync's delta merge comes up for me: For all of my virtual machines, I build a bootable live ISO so that way I can cleanly swap out the full ISO with a new one when there are software updates. This means that every time I want to change a config file inside the virtual machine, I end up building a new ISO and rsyncing it to my server. rsync speeds this up significantly since most (but not all) of the ISO is unchanged.
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.
I'm eager to replace battle-tested rsync with a new half-baked tool that no one uses for a tiny speed improvement. I'm also going to enable automatic updates of that tool too.
> I also added cool features like the ability to maintain a persistent ssh connection to the server for fast one-offs
rsync already supports this via OpenSSH's ControlMaster directive. Bonus, it speeds up every connection to that server rather then a single tool's.
> the ability to do direct remote-remote transfers without forwarding your ssh agent (by using restricted ssh keys on the receiver that will only execute a specific request signed with the key on your laptop).
You can control your agent forwarding in your local ssh client configuration. And with modern ProxyJump, you don't need to forward your agent at all regardless of how many bastion hops are between you and your final target.
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.
I thought I'd share a more positive comment. I work on a tool in a similar area (moving stuff around) but on a higher level. I currently use rsync or rclone for the file moving parts. So to me your tool looks interesting and promising, thanks for sharing it :)
Some suggestions for improvement for your website/Github:
- I wanted to understand how it differs from rsync. A comparison page would be helpful.
- A comparison to rclone would also be interesting, as it also uses multiple parallel connections.
- As it target more advanced users I think it would be helpful to provide more advanced technical insights on how your transfers exactly work. Also how are edge cases handled, what tests are done? Moving and copying files is critical, and you need to inspire trust in your project among users.
Thank you for showing this. I'll echo what some others say: if you're claiming to be faster than rsync, you should demonstrate why front-and-center. There have been decades of documentation on how rsync optimizes transfers, so it's a lot to live up to.
As an aside, It's perhaps an indictment of our networking landscape that multiple parallel connections between 2 specific machines would accelerate a transfer. I would've expected a single TCP connection to be able to saturate a line. Or perhaps the parallel connections seeks to amortize the per-file setup overhead?
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 had 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.
Very cool!
How does the direct TCP mode work?
Currently, there is just a fixed range of ports that it will use if they are open and you don't pass `--no-tcp`. It does its own encryption over the TCP connections. Also worth knowing is that for some connections (e.g. if there are any dropped packets), you may get much better performance if you can enable BBR congestion control. https://greaber.github.io/syq/server-tuning.html#test-conges...
Why is this better than rsync?
Browsing the repo, I can see a couple of advantages:
- Single contributor. Software bugs are generally caused by developers writing code. By reducing the number of contributors, syq has cleverly reduced the surface area for defects to sneak in.
- Distribution via shell script. rsync is bundled in most linux distributions, which means you have to deal with annoying software updates from time to time. Syq, OTOH, tells you to pipe curl into bash to execute a shell script, which means one-and-done installation and maintenance.
- UI clarity. If you search StackOverflow for rsync, you'll see thousands of questions asking how to accomplish various tasks with rsync, both straightforward and arcane. By contrast, `syq` isn't even a tag on SO. The obvious conclusion here is that rsync's interface is so byzantine, and its documentation so poor, that users must resort to asking strangers for help, a problem obviously not shared by syq.
- No need to be snarky. It's a new project, while rsync is time tested, and that is certainly an advantage for rsync and all old software.
- You can install by piping curl to bash, using brew, or by compiling yourself. One thing about distribution I would argue syq gets right is that you are never relying on whatever version of syq happens to be installed on a server. The client syq always talks to a server syq tagged with the exact same version, and when your local copy of syq installs a remote copy, it verifies that the remote binary is signed by me.
- I never said or implied that rsync has a byzantine interface or poor documentation. I think rsync is well documented and the interface is overall fine. Syq even has an rsync compatibility mode, so you don't have to learn any new syntax if you don't want. Still, I tried to provide good docs for syq too, and honestly even if there were a gap in the docs, all you have to do these days is ask AI to look at the source code and tell you what to do. I think this also mitigates the trust issue with a new project from a single contributor.
How do you hope to convince sys-admins to install this? I work with clusters where I do not have superuser access, so this is a no go for me.
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.
Honestly, that's even scarier for an untrusted/low trusted tool...
There are a bunch of reasons, some of which are explained in the description and in the docs. For me, the most important benefit is speed of copying. Note that syq doesn't currently implement rsync's delta merge algorithm, which allows it to avoid copying data that is already in the destination file but at a shifted offset. I might implement this (or an enhanced version of it) in the future. If your workloads have a lot of cases like this then syq might not be better than rsync for you, but I found that for me this rarely came up.
One instance where rsync's delta merge comes up for me: For all of my virtual machines, I build a bootable live ISO so that way I can cleanly swap out the full ISO with a new one when there are software updates. This means that every time I want to change a config file inside the virtual machine, I end up building a new ISO and rsyncing it to my server. rsync speeds this up significantly since most (but not all) of the ISO is unchanged.
How do you handle updates this way? Do you mount the iso, update and keep it as an iso? Are all of the virtual machines mostly read only?
> Note that syq doesn't currently implement rsync's delta merge algorithm
That, and still claiming it’s “better than rsync”? Seems like you shouldn’t compare it with rsync (yet, if doing delta merges is planned)
There's something vastly superior over rsync still: "btrfs send" and "btrfs receive" (but require you to have btrfs on source and destination).
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.
I'm eager to replace battle-tested rsync with a new half-baked tool that no one uses for a tiny speed improvement. I'm also going to enable automatic updates of that tool too.
I'm seeing 5x speedups on my real workloads, and you can see some synthetic benchmarks here or run your own https://greaber.github.io/syq-bench/
You live up to your username!