Daemons

Overview

The daemon server provides UF Research Computing users with the space and resources to run long-running processes that do not require a lot of computational power. Please remember that these types of processes cannot be run on the login servers.

Daemon processes run in the background of a system rather than under the direct control of an interactive user. There are many uses for daemon tasks, from polling the batch system to collecting data from external sources. Daemon tasks are usually long-running or scheduled to run recurrently. They are also characterized by a small computational footprint (i.e., low average CPU and RAM usage). Daemon processes should not use 100% of a CPU for extended periods and such processes will be killed without warning.

Access to the daemon server

Connect to the cluster (hpg.rc.ufl.edu) and use the ssh command to access the daemon server.

ssh daemon

The daemon node is not accessible directly from outside of the cluster.

Running daemon processes

There are two ways to run a process in the background:

1. Add an ampersand (&) to the end of the command

my.process.sh &

2. Start the process and once it is running, type

control-Z + b + g

Setting up recurring tasks with Cron

You can schedule a task to run recurrently with Cron, a time-based job scheduler by editing your crontab file on the daemon server. Click here for more detailed instructions.