Agent Host System Utilization

Note: Performance varies by environment and you may or may not see similar results.

Generally, a Nessus Agent uses 40 MB of RAM (all pageable). A Nessus Agent uses almost no CPU while idle, but is designed to use up to 100% of CPU when available during jobs.

To measure network utilization when uploading results, Tenable monitored Agent uploads intoTenable.io over a 7 day period. Of over 36,000 uploads observed:

  • The average size was 1.6 MB.
  • The largest size was 37 MB.
  • 90% of uploads were 2.2 MB or less.
  • 99% of uploads were 5 MB or less.
  • Nessus Agent consumes 40 MB of RAM when dormant.
  • The Watchdog service consumes 3 MB.
  • Plugins consume approximately 300 MB of disk space (varies based on operating system). However, under certain conditions, disk usage can spike up to 2GB, e.g. when a plugins-code.db defragmentation operation is in progress.
  • Scan results from Nessus Agents to Nessus Manager and Tenable.io range between 2-3 MB.
  • Check-in frequency starts at 30 seconds and is adjusted by Nessus Manager orTenable.io based on the management system load (number of agents).