Monitoring data usage in Hermes

concept brazil Updated Sep 10, 2026 6 min read monitoring-data-usage-hermes.md
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Monitor the amount of data produced to and consumed from the Hermes cluster over time. Use the Hermes Usage Dashboard to track data inflow and outflow by topic, application, and time period.

[Omitted video] Description: Hermes Usage Dashboard overview video.

This video covers the Hermes Usage Dashboard.

Usage data is calculated by aggregating the size of all messages sent to the cluster. The size of the message is determined by the total payload present in Kafka, including key, header, value, and overhead. If compression is enabled, the dashboard reports the compressed payload size, which includes key, header, and message.

Key benefits

  • Monitor Hermes performance with insights into data inflow and data outflow in megabytes for a specified time period.
  • Visualize data usage over time for all topics, a single topic, or multiple applications.
  • Compare data usage for topics that belong to an application.

[Omitted image "hermes-usage-dashboard.png"] Alt text: Usage Dashboard showing data inflow and outflow metrics by topic and time period.

Required roles

The hermes_admin role is required to view the Hermes Usage Dashboard.

Accessing the Hermes Usage Dashboard

View usage by navigating to All > Hermes Messaging Service > Usage Dashboard.

Multi-select for Application ID filter

The Application ID filter displays full descriptive names alongside application identifiers so you can identify and select the application without needing to know internal shorthand codes. Only applications with active metrics collection appear in the filter.

Application ID Display Name
idr Instance Data Replication
cnc ITSM DEX
sn_streamconnect Stream Connect
sn_logstoanalytics Log Export Service

The Application ID filter supports selecting multiple applications simultaneously. With the multi-select option, you can do the following:

  • Compare data usage across multiple applications in a single view.
  • View aggregate Total MB In and MB Out across all selected applications.
  • View Topic Usage Data table with a separate row per selected application.

For example, you can select both IDR – Instance Data Replication and Stream Connect to view their combined and individual usage side by side.

Use cases

  • Monitor data usage for an application. Determine if usage has increased or decreased over time.
  • View data usage for a specific topic. Determine if usage patterns changed by looking for spikes or drops in usage.
  • Compare data usage for topics in a single application or all applications that belong to you.
  • Analyze total bytes in and bytes out based on the source.
    • Instance

      Total bytes sent to and consumed from a topic by the instance. For example, select Instance to view log volume produced to a topic by Log Export Service.

    • Customer

      Total bytes sent to and consumed from a topic by an external customer application. For example, select Customer to view log volume consumed from a topic by an external application.

    • Other

      Total bytes sent to and consumed from a topic by an internal ServiceNow application.

    • All

      Aggregation of all Consumer, Instance, and Other values.

Reports

Data displayed in the Hermes Metrics Dashboard is collected from the Hermes usage metrics [hermes_usage_metrics] table.

  • Metric data is captured hourly, with each collection point reflecting the latest value recorded within that hour.

  • Metric data is aggregated and displayed over time. This means the dashboard enables you to view an overall trend rather than precise moment-to-moment traffic.

  • Metric data displayed on the dashboard is initially aggregated daily. The dashboard automatically determines the best aggregation based on the date range selected:

    • Previous months: Data is displayed using monthly aggregates, giving you a clean summary of usage for each completed month.
    • Current month: Data is displayed using daily aggregates, so you can see up-to-date usage as it accumulates throughout the month.
    • Today: When your end date is today, hourly data is included, giving you the most current view of usage activity.
  • Metric data is retained for 12 months.

    If your selected date range spans both past and current months, the dashboard combines monthly summaries for the historical portion with daily and hourly data for the current period. For example, querying January 1 – April 9 (today is April 9).

    Period Aggregation
    January Monthly
    February Monthly
    March Monthly
    April 1 – April 8 Daily
    April 9 (today) Hourly

    The line graph has also been updated to display monthly trends when viewing extended date ranges, making it easier to identify long-term usage patterns.

Title Type Source table Description
Total Megabytes In Single score Hermes usage metrics [hermes_usage_metrics] table View the aggregated total of data produced to Hermes in megabytes.
Total Megabytes Out Single score Hermes usage metrics [hermes_usage_metrics] table View the aggregated total of data consumed from Hermes in megabytes.
Usage trends Trend Hermes usage metrics [hermes_usage_metrics] table Monitor data usage in terms of bytes in and bytes out for selected topics over time.
Topic Usage Data Table Hermes usage metrics [hermes_usage_metrics] table Monitor data usage (bytes in and bytes out) for all topics or specific topics.

Topic usage data

View data usage (bytes in and bytes out) by source based on the combination of application ID, service ID, and topic that you select.

The Topic Usage Data table displays only topics associated with a recognized application. Topics that were created without an Application ID no longer appear in the table or in the Hermes Topic filter.

The following are the available options in the Hermes Topic filter:

  • All - Summary — Displays one aggregated total row per selected application. Use this for a quick snapshot of overall usage.
  • All - Detailed — Displays individual rows per topic. Use this to identify which specific topics are driving the most data usage. The sum of all rows in All - Detailed equals the All - Summary total.
Application ID Hermes Topic Option What you see How you might use it
All All - Summary One aggregate row per selected application. Quickly compare total data usage across applications.
All All - Detailed Individual topic rows for all applications, excluding aggregate entries. Identify which specific topics are driving the most usage across your organization.
Single App All - Summary One aggregate row for that application. Get a total usage snapshot for a specific application.
Single App All - Detailed One row per individual topic for that application. Drill into topic-level usage for a specific application.
Multiple Apps All - Summary One aggregate row per each selected application. Compare total usage side by side across selected applications.
Multiple Apps All - Detailed One row per topic for each selected application. Analyze topic-level breakdown across multiple applications simultaneously.
Any Specific Topic One row for that topic. Focus on usage patterns for a single topic.

Parent Topic:Administering Hermes Messaging Service

Related topics

Managing Hermes settings

Check the status of and connection to the Hermes Kafka cluster

Tracking message usage in Hermes

Cloning with Hermes Messaging Service enabled

View Hermes Messaging Service log messages

Keywords Usage dashboardMonitor data usageUsage data
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