Long running ssh with network drops

[tasuki]

Hi, this is not a bug report, just something I'm very confused about.

My use case is (I have full control over both the laptop and the server.):

1. I ssh from my laptop into a server and run vim or whatever.
2. I put my laptop to sleep.
3. Wake up, I want to see my vim or whatever still open on the server.

I've used tmux for a long time. Kovid says tmux isn't necessary, so I try with kitty+kitten:

• When I run kitty +kitten ssh the session feels more persistent than a regular ssh session. It easily survives a couple minutes of sleep. Perhaps it does something similar to mosh?
• But when I put the laptop to sleep for the night, the session is gone.
• I'd like my sessions to survive sleep. I'm fine if they drop after 168 hours of inactivity.

It would be great if this was addressed in the docs, it's such a common use case! Or perhaps it is addressed and I just can't find it...

Anyways thank you for kitty, it's marvelous!

[kovidgoyal]

That cant be done, when you sleep your laptop, the remote side will eventually assume the connection is dead and drop the connection. You could theoretically configure the remote side to wait 10 hours before dropping connections, but this is slightly non-trivial to do as it means configuring the ssh daemon and the kernel on the remote machine and it can have unwanted side effects for other connections.

[tasuki]

Kovid, thank you for your response.

I know you've mentioned in the past that this hasn't been a problem for you. I wonder, do you not have any servers you sometimes ssh into? Or do you start everything from scratch every time you connect? Or, do you secretly use tmux? 😉

[tasuki]

Ah, another option I guess is to not put one's laptop to sleep. With new laptops not supporting S3 sleep, it doesn't matter much whether the laptop sleeps or not. Maybe I'm the weird one that I set my laptop to suspend on lid close...

[kovidgoyal]

I have been running servers with multi year uptimes for multiple decades, probably since before you were born. I have **never** used terminal multiplexers, they are a complete anti-pattern, and always were, even when terminals were far less capable than they are now. And I definitely do not appreciate the insinuation that I am lying about my usage of multiplexers, continue trying to make this personal and I will block you. As for your use case, if you really find yourself needing to stay logged into a remote server overnight, **and** you really want to sleep your laptop overnight, use one of the may non-multiplexing tools that preserve remote session across disconnects. Though personally, I would advise you to change your workflow to do actual work locally rather than when logged into a server and sync your changes to the server, that's a far more productive workflow in the long run. Good luck.

[tasuki]

[...] probably since before you were born [...] [terminal multiplexers bad]

Kovid, let's not have an age competition please. Look, I understand you're frustrated having to explain your position on terminal multiplexers ad nauseam. I get it, I get it.

And I definitely do not appreciate the insinuation that I am lying about my usage of multiplexers, continue trying to make this personal and I will block you.

It was not an insinuation from my part, it was a bad joke, as hinted by the emoji. (If you wanted to be pedantic about it, you could say it was a question). If you block me for making a bad joke, so be it. This is your space and you're free to do as you like. I'll continue using your amazing software anyway 😉

As for your use case, if you really find yourself needing to stay logged
into a remote server overnight, and you really want to sleep your laptop
overnight, use one of the may non-multiplexing tools that preserve remote
session across disconnects.

Right, such as mosh or EternalTerminal I guess?

Though personally, I would advise you to
change your workflow to do actual work locally rather than when logged
into a server and sync your changes to the server, that's a far more
productive workflow in the long run.

Why would it be more productive? Any pointers how to do that for things which can only run on the server? I'd like to have LSP working, and am wary of having to maintain two (fiddly) environments in sync, one for writing code, another for executing it. I'll need to maintain a connection to the server to execute the code anyway...

[kovidgoyal]

Once you impose the discipline of working that way you will find yourself making your environments less fiddly automatically, which will boost your long term productivity tremendously. It certainly did for me when I switched to that way of working many, many years ago.

And no I wasn't talking of mosh or eternalterminal. I was talking of tmux like tools that dont do multiplexing, just run remote programs in a single pty that they forward to the host terminal without actually having to implement a full terminal emulator themselves. That avoids the complexity cascade and all the associated problems of multiplexers. Though it retains the performance drawbacks, which to be fair, dont really matter in the remote case. For example abduco, though since I dont work this way I havent really kept up with this space. You should do your own research.

The other less bad alternative is to use a multiplexer that comes with the terminal so that it at least in theory should support everything the terminal does and work well. wezterm is an example of this approach. And someday I might get around to implementing such an approach in kitty, though since I wont have any use for it personally it's not a priority. My main motivation to do so would be to avoid having to repeat myself on this subject endlessly.

[tasuki]

I used to work with less fiddly environments. These days (some of) my environments are very fiddly, through – I hope – no fault of my own. The one I'm talking about depends on an amount of data that would hardly fit on my laptop. And requires GPUs that won't fit in my laptop. Plus it's extra fiddly as there's a lot of exploratory work going on.

Yes, preserving sessions is orthogonal to terminal. There are so many things that do both it took me a long time to notice they're two distinct things. I guess mosh will work for me, I don't care about scrollback very much. Thank you for taking the time to reply and explain.