WSL Terminal - Weird freezing issue

WSL Terminal - Weird freezing issue

by Rajagopal Vinod Bethi -

I am using WSL Terminal (Ubuntu) to SSH into the Fritz cluster. However, I have noticed a weird issue wherein if I don't use the terminal for some time, the terminal becomes unresponsive. I have tried to check if this issue occurs with my WSL Terminal in general, but I did not face any issue when I just open a terminal and let it idle for a long time. 

This issue only props up when the terminal is connected to Fritz cluster. Ctrl+C and Ctrl+Z also do not work and I have to manually close the terminal by hitting the Windows Close Button (The X at the corner). Last semester, I used the WSL Terminal to login to Emmy cluster and faced no such issue. 

Please let me know if any more information is required regarding this issue. It is generally not a major problem but when I connect to a node using salloc, the terminal freezing issue locks me out of the node and I have to cancel the job by logging in from another WSL Terminal. Another thing to note is that when I cancel the job from the other terminal, the original terminal that was logged in and froze, still continues to remain frozen. 

If anyone else is having this issue, please do let me know. Thanks

Re: WSL Terminal - Weird freezing issue

by Georg Hager -

Hi,

colleagues who use WSL have reported similar issues with SSH connections. It seems like the WSL terminal doesn't like short network outages, but that's only a wild guess. There are two things you can do that can improve the situation for you:

  1. In order to terminate the nonresponsive SSH connection, just type "~" followed by "." followed by the enter key. This three-key sequence will get you back to your local shell so you don't have to kill the whole terminal window. However, your connection (and your interactive job on fritz) is still lost.
  2. You can use a terminal multiplexer such as "screen" or "tmux" on a machine at the computing center, for example on cshpc. The terminal multiplexer is like a session with multiple windows from which you can detach anytime and reattach later to continue where you left off. We have an intro video about tmux at

    Using tmux you can connect to fritz from a session window. If your WSL terminal connection fails, just kill it with the key sequence (see above) and log in again at cshpc, then reattach to the running tmux session and you're back.
Even without terminal/connection problems, we strongly recommend using a terminal multiplexer. It makes your life so much easier.

Best,
Georg.