SymmetricDS Pro 3.9 User Guide

SymmetricDS is written in Java and requires a Java Runtime Environment (JRE) Standard Edition (SE) or Java Development Kit (JDK) Standard Edition (SE) version 8.0 or above. Most major operating systems and databases are supported. See the list of supported databases in the Database Compatibility section. The minimum operating system requirements are:

The memory, disk, and CPU requirements increase with the number of connected clients and the amount of data being synchronized. The best way to size a server is to simulate synchronization in a lower environment and benchmark data loading. However, a rule of thumb for servers is one server-class CPU with 2 GB of memory for every 500 MB/hour of data transfer and 350 clients. Multiple servers can be used as a cluster behind a load balancer to achieve better performance and availability.

SymmetricDS Pro is accessed from a web console, which requires one of the following supported web browsers:

A node is responsible for synchronizing the data from a database or file system with other nodes in the network using HTTP. Nodes are assigned to one of the node Groups that are configured together as a unit. The node groups are linked together with Group Links to define either a push or pull communication. A pull causes one node to connect with other nodes and request changes that are waiting, while a push causes one node to connect with other nodes when it has changes to send.

Each node is connected to a database with a Java Database Connectivity (JDBC) driver using a connection URL, username, and password. While nodes can be separated across wide area networks, the database a node is connected to should be located nearby on a local area network for the best performance. Using its database connection, a node creates tables as a Data Model for configuration settings and runtime operations. The user populates configuration tables to define the synchronization and the runtime tables capture changes and track activity. The tables to sync can be located in any Catalog and Schema that are accessible from the connection, while the files to sync can be located in any directory that is accessible on the local server.

At startup, SymmetricDS looks for Node Properties Files and starts a node for each file it finds, which allows multiple nodes to run in the same instance and share resources. The property file for a node contains its external ID, node group, registration server URL, and database connection information. The external ID is the name for a node used to identify it from other nodes. One node is configured as the registration server where the master configuration is stored. When a node is started for the first time, it contacts the registration server using a registration process that sends its external ID and node group. In response, the node receives its configuration and a node password that must be sent as authentication during synchronization with other nodes.

Each subsystem in the node is responsible for part of the data movement and is controlled through configuration. Data flows through the system in the following steps:

SymmetricDS offers a rich set of features with flexible configuration for large scale deployment in a mixed environment with multiple systems.

SymmetricDS is a feature-rich data synchronization solution that focuses on ease of use, openness, and flexibility. The software encourages interoperability and accessibility for users and developers with the availability of source code, an application programming interface (API), and a data model supported by documentation. Configuration includes a powerful set of options to define node topology, communication direction, transformation of data, and integration with external systems. Through scripts and Java code, the user can also extend functionality with custom behavior. With a central database for setup and runtime information, the user has one place to configure, manage, and troubleshoot synchronization, with changes taking immediate effect across the network.

The trigger-based data capture system is easy to understand and widely supported by database systems. Table synchronization can be setup by users and application developers without requiring a database administrator to modify the server. Triggers are database objects written in a procedural language, so they are open for examination, and include flexible configuration options for conditions and customization. Some overhead is associated with triggers, but they perform well for applications of online transaction processing, and their benefits of flexibility and maintenance outweigh the cost for most scenarios.

Using an architecture based on web server technology, many simultaneous requests can be handled at a central server, with proven deployments in production supporting more than ten thousand client nodes. Large networks of nodes can be grouped into tiers for more control and efficiency, with each group synchronizing data to the next tier. Data loading is durable and reliable by tracking batches in transactions and retrying of faults for automatic recovery, making it a low maintenance system.

SymmetricDS Pro is commercial software that is licensed, not sold. It is subject to the terms of the End User License Agreement (EULA) and any accompanying JumpMind Support Contract. See the standard SymmetricDS Pro license for reference, but your agreement with JumpMind may be different.

The SymmetricDS installer is an executable jar file named symmetric-pro-<version>-setup.jar. In order to run the installer, you must have the Java Runtime Environment (JRE) version 6.0 or newer installed. Start the installer by double-clicking it (if the JRE is in your path and associated with .jar files), or by running it from a command prompt, like this:

java -jar symmetric-pro-<version>-setup.jar

The default installation will run in graphical mode, but it can also be run from a command window by adding the -console argument on the end of the command.