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Center for High Throughput Computing

Using CHTC's HTC Submit Nodes

If you have not yet requested a CHTC account and met with a Research Computing Facilitator, please fill out this form.

Recently created CHTC accounts will use our submit node submit-5.chtc.wisc.edu. If your CHTC account was created in 2016, you will use submit-3.chtc.wisc.edu. If your CHTC account was created in 2015, you will use submit-5.chtc.wisc.edu. Accounts created prior to 2015 will most likely use submit-3.chtc.wisc.edu. Access to other submit nodes is granted for specific purposes and will have been indicated to you by CHTC staff.

Connecting to CHTC Submit Nodes

When your CHTC account is active, you can connect to one of our submit nodes with an SSH connection ("Putty" for Windows, putty.org; "Terminal" for Linux/Max). Note, however, that our submit nodes only accept connections from campus networks. Off-campus connections have been disabled for security purposes. If you need to connect from off campus, you can first SSH to a computer in your department, and then SSH to our submit node. You may also be able to use a Virtual Private Network (VPN) to join the campus network when working off-campus. DoIT provides information on using a VPN.

Data Practices

We do not back up data on CHTC submission points, and users should treat CHTC compute systems as temporary storage locations for active, currently-queued computatioal work. Users should remove data from CHTC systems upon completion of a batch computational work and keep copies of all essential files in a non-CHTC location. CHTC staff reserve the right to delete data from any CHTC file systems at at any time, to preserve performance, and are not responsible for data loss for file system corruption, which are possible, especially in the absence of back-ups.

Submit Node User Policies

Because our submit nodes are shared by many CHTC users, anyone with an account on CHTC's submit nodes should follow the below policies, in order to keep the submit nodes funcational and usable by everyone:
  • Do not share accounts. We are happy to make new a new account for any user. Sharing accounts is against campus policy and, therefore, CHTC policy. Accounts that we notice being shared will be immediately disabled and a meeting with the PI (faculty advisor) will be necessary to reinstate the account.
  • Do not run programs on the submit node. The submit node is kept plenty busy just managing HTCondor jobs. Computational work, like compiling code, should be submitted as HTCondor jobs. See our online guides for the best compiling practices. Small scripts and commands (to compress data, create directories, etc.) that run within a few minutes on the submit node are okay, but their use should be minimized when possible.
  • Jobs with long runtimes. There is a default run limit of 72 hours for each job queued in the HTC System, once it starts running. Jobs longer than this will be placed in HTCondor's "hold" state. If your jobs will be longer, please email us, and we'll help you to determine the best solution.
  • Submitting many jobs from one submit file. HTCondor is designed to submit thousands of jobs from one submit file. However, submitting too many jobs at once provides no extra benefit to the submitter and can make the queue work more slowly. If you are submitting over 10,000 jobs per submit file or have submitted over 50,000 jobs at once as a single user, please email us as we have strategies to submit that many jobs in a way that will ensure you have as many jobs running as possible without also compromising the queue.
  • There is a 20 GB disk quota in your /home directory, by default. You can track your use of disk space, and your quota value, using our Quota Guide. If you need more space for concurrent work, please send an email to chtc@cs.wisc.edu.
  • Submitting jobs with "large" files: Please do not submit jobs that require single input files larger than 100 MB using HTCondor's normal file transfer mechanism ("transfer_input_files"), or that produce output files greater than a few GB. For such jobs with large files, please see our guide on File Availability Options, and contact us to make arrangements.
  • No scheduled jobs. Local execution and job submission should be manual, or use a DAG. Do not use cron to schedule jobs, and do not submit jobs with a script that uses "sleep" or otherwise doesn't complete while you are logged in. Contact us if you need job scheduling.