Why do I receive .Xauthority file error messages?

When you open a new terminal session on mistral with X forwarding turned on (ssh -X ...), the .Xauthority file in your home directory gets updated by the xauth program. This file is used to keep X authentication keys in order to prevent unauthorized connections to your local display.

Sometimes, the .Xauthority file cannot be updated due to issues with the lustre01 file system, where your home directory is located, on mistral and you might experience an error message like:

/usr/bin/xauth:  error in locking authority file ~/.Xauthority

/usr/bin/xauth:  timeout in locking authority file ~/.Xauthority

In general, problems with your .Xauthority file should not prevent you from logging in, but X11 forwarding will fail if you receive one of the error messages above. In case of severe lustre errors, the login to mistral might also hang. To ensure that the login failure is caused by lustre issues (and not by specific issues of your user account or local system) you can first check DKRZ system notifications or system status monitor.

If the above does not apply, please provide the debug output of the ssh command

ssh -v -X <userid>@mistral.dkrz.de

and information about your operation system to support@dkrz.de.

To clean up stale locks of .Xauthority file you can try the following command:

xauth -b -f ~/.Xauthority

or simply rename the .Xauthority file if you think it might be corrupted. A new .Xauthority file will automatically be created on login.