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Bar Gauge Panels

Introduction​

Bar Gauge panels are one of Grafana's most effective visualization tools for displaying single-value metrics with thresholds. Unlike standard gauges that use a dial or meter, Bar Gauges represent values as colored bars, making them excellent for dashboards where you need to monitor multiple related metrics at a glance.

In this guide, you'll learn:

  • What Bar Gauge panels are and when to use them
  • How to create and configure Bar Gauge panels
  • Different display modes and orientation options
  • How to set up thresholds and color mapping
  • Real-world applications and best practices

What is a Bar Gauge Panel?​

A Bar Gauge panel is a visualization type in Grafana that displays single values as colored bars or circles. It's particularly useful for showing:

  • Current values against thresholds
  • Progress toward goals
  • Health status of services or components
  • Resource utilization metrics (CPU, memory, disk space)

The key advantage of Bar Gauge panels is their visual clarity and space efficiency - they allow you to display multiple metrics in a compact, easily scannable format.

Creating Your First Bar Gauge Panel​

Let's walk through creating a basic Bar Gauge panel in Grafana:

  1. From your Grafana dashboard, click the "Add panel" button
  2. Select "Add a new panel"
  3. In the visualization options, select "Bar Gauge"
  4. Configure your data source and query to return a single value

Here's what a simple configuration might look like:

// Example query returning CPU usage for a server
SELECT
  last("usage_idle")
FROM "cpu"
WHERE $timeFilter
GROUP BY time($__interval)

Display Modes​

Bar Gauge panels offer multiple display modes to suit different visualization needs:

1. Basic (Default)​

The basic mode displays values as horizontal or vertical bars, depending on your orientation setting.

2. Gradient​

Gradient mode applies a color gradient across the bar based on your thresholds, creating a smoother visual transition between states.

3. LCD​

LCD mode mimics a digital display, showing the value as segments similar to an LCD screen. This mode works well for numeric displays where you want a technical aesthetic.

4. Retro LCD​

A variation of LCD mode with a more vintage appearance, featuring rounded segments.

To change the display mode:

  1. Go to the "Display" tab in the panel editor
  2. Find the "Display mode" option
  3. Select your preferred mode from the dropdown

Orientation Options​

Bar Gauge panels can be displayed in different orientations:

  • Horizontal (default): Bars extend from left to right
  • Vertical: Bars extend from bottom to top

To change orientation:

  1. Go to the "Display" tab
  2. Find the "Orientation" option
  3. Select either "Horizontal" or "Vertical"

Value Display Options​

You can customize how values are displayed within your Bar Gauge:

Text Size and Mode​

Control the size of text and how it's displayed:

// Example panel JSON config showing text options
{
  "options": {
    "text": {
      "titleSize": 16,
      "valueSize": 32
    }
  }
}

Units and Decimals​

Configure appropriate units and decimal precision:

  1. In the "Field" tab, find the "Standard options" section
  2. Set the "Unit" to an appropriate measurement (percentage, bytes, etc.)
  3. Adjust "Decimals" to control precision

Value Mapping​

Map specific numeric values to text for better context:

  1. In the "Field" tab, find "Value mappings"
  2. Click "Add value mapping"
  3. Choose between "Value", "Range", or "Regex" mapping types
  4. Define your mappings (e.g., map 0 to "Offline" or 100 to "Full Capacity")

Thresholds and Color Mapping​

One of the most powerful features of Bar Gauge panels is threshold-based coloring, which helps highlight values that need attention.

Setting Up Thresholds​

  1. Go to the "Field" tab in panel edit mode
  2. Find "Thresholds" and click "Add threshold"
  3. Define your threshold values and corresponding colors

For example, a server health metric might use:

  • 0-70: Green (healthy)
  • 70-90: Yellow (warning)
  • 90-100: Red (critical)
// Example threshold configuration
{
  "thresholds": {
    "mode": "absolute",
    "steps": [
      { "color": "green", "value": null },
      { "color": "yellow", "value": 70 },
      { "color": "red", "value": 90 }
    ]
  }
}

Color Mode Options​

You can choose how colors are applied to your bar gauges:

  • Value: Colors only the value text
  • Background: Colors the entire background
  • Bar: Colors only the bar (most common)

Multiple Stats in One Panel​

Bar Gauge panels excel at displaying multiple related metrics in a single panel:

  1. Configure your query to return multiple series
  2. Each series will automatically be displayed as a separate bar
  3. Use the "Layout" options to control how multiple bars are arranged

For instance, to show CPU usage across multiple servers:

// Example query returning CPU usage for multiple servers
SELECT
  last("usage_idle")
FROM "cpu"
WHERE $timeFilter
GROUP BY "host"

Practical Example: Server Resource Dashboard​

Let's create a practical example of using Bar Gauge panels to monitor server resources:

// CPU Usage Query
SELECT 100 - mean("usage_idle") as "CPU Usage %" 
FROM "cpu" 
WHERE $timeFilter 
GROUP BY time($__interval)

// Memory Usage Query
SELECT mean("used_percent") as "Memory Usage %"
FROM "mem"
WHERE $timeFilter
GROUP BY time($__interval)

// Disk Usage Query
SELECT mean("used_percent") as "Disk Usage %"
FROM "disk"
WHERE $timeFilter
GROUP BY time($__interval)

Configure these with appropriate thresholds:

  • 0-60%: Green
  • 60-85%: Yellow
  • 85-100%: Red

This creates a compact dashboard showing all key server metrics at a glance, with color-coding to immediately highlight potential issues.

Advanced Configurations​

Min and Max Values​

Control the scale of your bar gauges by setting min and max values:

  1. In the "Field" tab under "Standard options"
  2. Set "Min" and "Max" values (e.g., 0 and 100 for percentage displays)

Calculation Options​

For time series data, you can control how the single value is calculated:

  1. In the "Panel options" section
  2. Find "Calculation" and select from options like:
    • Last value
    • Mean
    • Max/Min
    • Total

Custom Tooltips​

Enhance your Bar Gauge with informative tooltips:

// Example tooltip configuration
{
  "options": {
    "tooltip": {
      "mode": "single",
      "sort": "none"
    }
  }
}

Real-World Applications​

Bar Gauge panels are versatile and can be used in many scenarios:

1. Infrastructure Monitoring​

Monitor server farm health with bar gauges showing:

  • CPU usage
  • Memory utilization
  • Network throughput
  • Disk space

2. Application Performance​

Track application metrics:

  • Request latency
  • Error rates
  • Active users
  • Queue depths

3. Business KPIs​

Visualize business metrics:

  • Sales targets (% achieved)
  • Customer satisfaction scores
  • Project completion percentages
  • Inventory levels

4. IoT and Sensor Data​

Display sensor readings:

  • Temperature ranges
  • Humidity levels
  • Battery levels
  • Signal strength

Best Practices​

DO:​

  • Use consistent colors across your dashboard
  • Group related metrics together
  • Set appropriate min/max values for context
  • Add clear titles and descriptions
  • Use appropriate units

DON'T:​

  • Mix unrelated metrics in a single panel
  • Overcrowd panels with too many bars
  • Use Bar Gauges for time series trends (use Graph panels instead)
  • Set arbitrary thresholds without business context

Summary​

Bar Gauge panels are powerful tools in your Grafana visualization toolkit. They excel at displaying single-value metrics with threshold context in a compact, visually intuitive format. By properly configuring display modes, thresholds, and orientation, you can create information-dense dashboards that communicate status at a glance.

Remember these key points:

  • Bar Gauges are ideal for single values, not trends over time
  • Use thresholds to add context through color
  • Multiple related metrics can be grouped in one panel
  • Different display modes (Basic, Gradient, LCD) offer visual variety
  • Proper unit selection enhances readability

Additional Resources​

  • Practice creating different types of Bar Gauge panels with various display modes
  • Experiment with combining Bar Gauges with other panel types in a dashboard
  • Try creating a resource monitoring dashboard for your own infrastructure

Exercise​

Create a dashboard with the following Bar Gauge panels:

  1. A horizontal Bar Gauge showing CPU usage
  2. A vertical Bar Gauge showing memory usage
  3. An LCD-style gauge showing disk space
  4. A multi-stat Bar Gauge showing network metrics for different interfaces

Configure appropriate thresholds and experiment with different display options to see which works best for each metric type.

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