The Bluecrab cluster is used by hundreds of users on a daily basis. The Bluecrab cluster has a few login nodes where all users connect to conduct their computing and research. The login nodes are an interface between all compute nodes and the users. We all need to follow good practices to create a friendly environment and ensure that one’s activity does not negatively impact the system and many or all other users.

DO NOT run jobs on the login nodes: Login nodes are used by hundreds of users to monitor their jobs, submit jobs, edit and manipulate files and sometimes to compile codes. We strongly request that users abstain of running jobs on login nodes. Sometimes users may want to run quick jobs to check that input files are correct or scientific applications are working properly. If this is the case, make sure this activity does not take more than a couple of minutes or even better request an interactive session (interact) to fully test your codes.
Do not perform activities that may impact the file systems, for example rsync or copying large or many files from one file system to the other. Please use Globus (FAQs) to transfer large amounts of data.
In short, do not run jobs or perform intensive com Your account may be suspended and you will lose access to the queues if your activities are impacting other users.

What is allowed on login nodes:

  1. Request an interactive session “interact -usage”
    • interact -X
    • compute0717> matlab
  2. Compile your codes, for example run “make”. Be careful if you are running commands with multiple processes, for example while “make -j 4” may be fine, “make -j 20” may impact other users.
  3. Check your jobs
    • “sqme”
  4. Edit files, scripts, manipulate files
  5. Submit jobs
    • sbatch script-name
  6. Look at output files
    • more file-name

What is NOT allowed:

  1. run jobs (./a.out)
  2. rsync or copy large number of files
  3. run applications like Matlab (use an interactive session)
  4. Minimize the use of certain commands like:
    • “ls –color”
    • df
    • top