Login node¶
One connects to the VSC systems through the use of "login nodes". They serve as a connection between VSC and the outside world.
Login nodes are a shared resource that are used among all the users logged in into the system, as such, if it becomes slow or it crashes all users are affected. For this reason we do not allow you to run anything but the most essential things on the login node.
On the login node, one can:
- Submit batch and interactive jobs.
- Copy, edit, and delete files.
- Transfer files from and to the system.
- Run applications that use small amounts of CPU and memory.
- Compile code (4 threads max).
Running on the login node
Do not run compute-, memory-, or i/o-intensive applications on login nodes. These nodes are shared resources. VSC may terminate processes that negatively impact other users or the systems.
Please, don't run things that will inconvenience other users. The risk of affecting other users increases with the more CPU and memory you use, and the longer you use it.
If VSC gets complaints from other users or by automatic monitoring about improper use of the login node, we will kill your processes. An email notification will be send if this happens.
User behavior can the login node, you can read more about slow login node behavior here.
Usage Limits¶
None the less, VSC has implemented usage limits on login nodes via Linux cgroup limits with the purpose of avoiding unintentional overuse of resources and provide a better interactive experience for all VSC users.
The following memory and CPU limits have been put in place on a per-user basis (all processes combined from each user):
Node type | Memory limit | CPU limit |
---|---|---|
login | 24Gb | 4 cores |