Troubleshooting

SSH Host Key Verification (First-Time Setup)

When using Scion for the first time, you must manually SSH into the target server from a terminal before Scion can connect. This is required for two reasons:

1. SSH host key verification – SSH requires you to accept the server’s host key on first contact, and Scion cannot handle this interactive prompt.
2. User home folder creation – your home directory on the server is created automatically on your first SSH login. Without it, Scion will not be able to browse or transfer files to the server.

macOS / Linux

Open a terminal and run one of the following, depending on which server you plan to use:

# For fileserver
ssh your-username@fileserver-ssh.mpi-cbg.de

# For korok
ssh your-username@korok.mpi-cbg.de

When prompted with:

The authenticity of host 'fileserver-ssh.mpi-cbg.de (...)' can't be established.
...
Are you sure you want to continue connecting (yes/no)?

Type yes and press Enter. You can then close the SSH session. After this, Scion will be able to connect to the server without issues.

Windows

Open PowerShell or Command Prompt and run:

# For fileserver
ssh your-username@fileserver-ssh.mpi-cbg.de

# For korok
ssh your-username@korok.mpi-cbg.de

Accept the host key when prompted. If ssh is not available, install OpenSSH for Windows or use PuTTY to connect to the server once.

Connection Fails After First Login

If Scion shows a connection error even after accepting the SSH host key:

1. Check your credentials – make sure the username and password are correct.
2. Check network access – ensure you are on the MPI-CBG network or connected via VPN.
3. Check server availability – the server may be temporarily down for maintenance.

Transfer Stalls or Fails

• Large files: rsync may appear to stall on very large files. Wait a moment before stopping the transfer.
• Disk space: verify that the destination has enough free space.
• Network interruption: if the network drops during transfer, Scion will resume from where it left off on the next attempt thanks to rsync’s incremental transfer.

Reporting Issues

If none of the above resolve your problem, please contact scicomp@mpi-cbg.de or open an issue on GitHub.