Daemons

According to Wikipedia, as daemon is "is a computer program that runs as a background process, rather than being under the direct control of an interactive user."[1] There a many uses for daemon tasks from polling the batch system to collecting data from external sources. The features that unify these tasks is that they are long running (or scheduled with cron) and that they have a small computational footprint.

It is against UF Research Computing policies to run any interactive or long running process on the login nodes or the development servers. To fill the need users have to run these tasks we have deployed a server dedicated to daemon tasks.

Access to daemon server

Access to the daemon server is via ssh from one of the login servers for the cluster. For example, after connecting to gator.rc.ufl.edu, you can type:

ssh daemon1

Running daemon processes

Once connected to daemon1, you can start your daemon process and have it run in the background. Please note that as specified above, daemon processes use few resources--daemon processes that use 100% of a CPU for extended periods negatively impact the performance of this server for other users and will be killed without warning.

To run a process in the background, either add a & to the end of the command, e.g.

my.process.sh &

or start the process and once it is running, type control-Z and then bg to run it in the background.