 a built-in backup node that keeps Litmus Edge running when the primary node goes down or is taken offline. The secondary node stays in sync and takes over automatically if the primary fails to protect your configuration and state. High Availability works reliably even with low bandwidth or uncertain connectivity. High Availability gives you continuous data collection with predictable recovery times and less unplanned downtime.

After configuring HA, the system ensures that the backup node is not the same as the primary node (not the self) and checks for version compatibility and license status. HA also provides handling for:

Offline scenarios with either the primary node or backup node

Disabling and enabling High Availability again

When enabled, high availability performs regular heartbeat checks at 2-second intervals. When the threshold for consecutive missed heartbeats is reached, the system initiates failover (3 missed heartbeats). Heartbeat activity, current role, rsync status, and sync timestamps are recorded in log files.

The following information displays on the primary node after you configure High Availability: 

: Last heartbeat sent to the backup node

: Last heartbeat received from the backup node

: Number of consecutive missed heartbeats

: Whether the backup is reachable from the primary.

: Frequency of heartbeat signals in seconds.

: Maximum number of missed heartbeats that trigger a backup.

 High availability is available as a beta feature only.

First enable the primary node, then enable the backup node, and finally provide backup information to the primary. 

On the instance that you will use as the backup node:

Copy the hostname and token values to a text editor. These values will not display again after you close this page.

On the instance that you will use as the primary node:

Paste the hostname and token values from the backup node into the 

Support

High Availability

Organize Device and Tag Data by Using Metadata

Use the Write Topic to Send Data to a PLC

Use the Batch-Write Topic to Send Multiple Write Requests

Use the Manage Topic to Stop a Device

Use the PLC-Status Topic to Verify Connection Status

Use the Poll-Once Topic to Manually Retrieve Register Values

Use the Status Register to Connect a PLC

Use the Siemens S7CommPlus Driver to Read Optimized Data Blocks

Tag Data Type Conversions

Use the Siemens S7 Browse Agent

Use the OPC UA Client Advanced driver for OPC UA Alarms & Events

Use the Mazak MTConnect Demo Agent to Connect a Device

DeviceHub Guides

Litmus Technical Documentation

Litmus Edge 4.0.x

System Architecture

User Journey

Flows and Analytics Explained

Overview

Establishing a Litmus Edge-Litmus Edge Manager Connection From the Litmus Edge Side

System Requirements

ISO Installation on Hypervisors

ISO Installation on an Industrial PC (IPC)

OVA Installation on Virtual Machine

Docker Installation

Kubernetes Installation

Zerotouch Installation

Raspberry Pi Installation

Developer Edition 2-Hour Trial

License Server Installation

Software Updates

Installation and Deployments

Access the Terminal User Interface

Access the Litmus Edge Web UI

Deprecated Drivers

Allen-Bradley

Atlas Copco

BACnet

Beckhoff

Brother Industries Ltd

CAN Bus

CodeSys Devices

Danfoss

Delta PLC

DNP3

Emerson

Euromap63

Excel

Fanuc Corporation

Fuji Devices

GE Fanuc

Generic

GPIO

Heidenhain

HID Devices

Hitachi Devices

Historian Drivers

Ignition Module

JTEKT Toyopuc

Keyence

Koyo

LS Industrial System

Lumberg Automation

Mitsubishi

Modbus

MQTT

MTConnect

Network Utility

ODVA

Omron

OPC UA

Opto Devices

Panasonic

Parker

Profinet

RS Automation

SAIA

Sick Flexi

Siemens

Simulator

Toshiba

VIPA

Yaskawa

Yokogawa

Industrial Systems Connection Guide

Quickstart Guide

Dashboard

Devices

Asset Discovery

Utilities

DeviceHub

Create and Import Models

Manage Models

Add an Instance

Manage Instances

Digital Twins

Configure the Timeseries DB

DB Management

DB Users

Edge Cascading v2

DataHub

Create a Flow

Manage a Flows Manager

Manage the Flow Canvas

Flow Canvas Dashboard

Function Nodes

Configuration Nodes

Flows Manager

Analytics Flows and Processors

Analytics Flow Groups

Instances Table

AI Models

Machine Learning Models

Input Processors

Output Processors

Statistical Functions

Key Performance Indicators

Analytics

Applications Dashboard

Catalog Apps

Configure

Marketplace

Containers

Networks

Images

Registry

Volumes

System Info

Disk Usage

Applications

Add a Connector

Add Topics to Connectors

Manage Connectors

Integration Connectors

Cloud Storage

Integration

Hierarchy

Management

Connections

OPC UA Server

Info

Activation

Device Management

Network

External Storage

Access Control

Events

System

Product Features

Use Digital Twins to Contextualize Data

Add a Device Certificate in Litmus Edge

Configure an External DataHub Source

Subscribe to Topics with Flows

Use Access to Write to a Topic

Use Access to Read from a Topic

Create, Write to, and Read from a Log File

Save Multiple Register Values to a CSV File

Work with SQL Databases

Work with MongoDB Databases

Write to Databases with Integration Topics

Create a Chart

Ping a Host

Send Alerts to a Mobile Phone

Create Audio Notifications for Sensor Readings

Flows Guides

Use the Anomaly Detection Function

Use the Base Conversion Function

Use the Combination Processor Function

Use the Change Processor Function

Use the Conversion Function

Use the Expression Processor Function

Use the Feature Extractor Function

Use the Gaussian Filter Function

Use the Inputs Processor Function

Use the JavaScript Processor Function

Use the Join Processor Function

Use the Linear Prediction Function

Use the Moving Window Processor Function

Use the Normalization Processor Function

Use the Rise and Fall Function

Analytics Guides