hkust-hpc-FAQs

FAQs for HKUST hpcs (SuperPOD, HPC4)

General usage

Q: Why I got "QOSMinGRES" error?

A: When allocating GPU nodes, please use --gres, --gpus-per-node or --gpus-per-task to specify the number of GPU requested.

Q: Why does my SSH session frequently disconnect during long operations?

A: SSH sessions can timeout due to network settings or inactivity. Here are solutions to maintain your connection:

1. Configure SSH Keep-Alive Settings: Add these settings to your ~/.ssh/config file:

Host ust-hpc4-login
    HostName hpc4.ust.hk
    User YOUR_USERNAME
    ServerAliveInterval 30
    ServerAliveCountMax 3
    TCPKeepAlive yes

2. Use Terminal Multiplexers, which keep the sessions alive when disconnect:

   • GNU Screen:

     # Start new session
     screen
     # Reconnect
     screen -r

   • Tmux:

     # Start new session
     tmux
     # Reconnect
     tmux attach

3. For Long Operations:

   • Use batch jobs instead of interactive sessions
   • Always run important processes in Screen/Tmux
   • Consider using nohup for background processes

Commands

For running an overlap job:

srun -A <account> --overlap --jobid <jobid> --pty bash