System Requirements - No Cluster

On this page you can find the (minimum) system requirements for the collaboration server, as well as for all optional modules, when running unblu on a 'Single Server' No Cluster framework (such as, for example, Apache Tomcat).

Note: This (no cluster) setup cannot be used to fulfill use cases requiring the unblu secure messenger.

Note: License requirements, supported browsers, video, database server, and mobile requirements are common to both Cluster (Kubernetes/Openshift - YAML) and no-cluster (WAR/EAR) installations. See Common Requirements.


While the server will run and the agent desk can be accessed, collaboration features will not function until you have uploaded your license. See licensing.

Supported Browsers

See: Supported Browsers

Collaboration Server

Hardware Requirements - Single Server - No Cluster

A single server setup (optionally with a hot standby) is the most robust, lowest cost to maintain, solution required to run a co-browsing infrastructure. To accommodate 10-20 concurrent co-browsing sessions (this means active usage of co-browsing in parallel), the following minimum requirements apply:

  • 1 Recent CPU core running at 2.4GHz
  • 4 GB RAM
  • 10 GB hard drive

Any additional 10-20 concurrent sessions require 1 additional core, 4 additional GB of RAM, and 4 additional Mbit of bandwidth.

With the outlined specs below, it is possible to scale up to 250 concurrent sessions.

  • Recent 16 core CPU with 2.4GHz or better
  • 64 GB RAM
  • SSD (min 100 GB available space on top of OS)
  • Gigabit Ethernet or fiber channel network

Memory Handling

It is not possible to predict exact memory usage, given traffic, concurrent use, page complexity, etc. However, server class JVMs use an initial 1/64 of physical memory with a maximum of 1/4 of physical memory. JVMs can use up to 32GB if there is 128GB of physical memory available. In the first example (above) 1GB will be automatically used for JVM 8. In the second example 16GB will be available.

If you want to fine-tune the heap size for the JVM see the following Oracle document:

Java Command Non-Standard Options

You can find further information on server class JVMs here:

Garbage Collector, Heap, and Runtime Compiler Default Selections

Client JVM Default Initial and Maximum Heap Sizes

We recommend you start with 4GB RAM and use the -Xmx (maximum allowed size) setting for fine-tuning.

The Collaboration Server is built to be deployed to any Servlet Container that supports Servlet API Version 2.5 or higher running on (at least) Java 8.

Note: The system requirements here are for unblu version 5. unblu 4.3 will only run with Java 8. (Any version of Java below, or above, Java 8 will not run with 4.3.)

Network Requirements

The collaboration server needs to be accessible via HTTP(S) visitor(s) and agent(s). In minimal configuration, the server does not communicate with other servers and does not require Internet access.

If additional modules are deployed see the following sections to find out which network connectivity requirements apply.

Minimal network bandwidth (10-20 concurrent sessions):

  • 4 Mbit

Any additional 10-20 concurrent sessions require 4 additional Mbit of bandwidth.

Rendering Service (universal and document co-browsing)

Document co-browsing and universal co-browsing, require the rendering service to be installed in addition. The rendering service is based on Docker. It requires a separate host to run docker with the rendering service docker image available at

Note: From version 4.2 onwards, the collaboration server requires the Docker rendering service tags to be version-specific to the collaboration server version used. So, if you use unblu 4.2 then 4.2 is the tag version number of the unblu Docker rendering service you must use. So, unblu 4.3 will use 4.3.

Rendering Service Hardware Requirements

Resource consumption is entirely dependent on the size of the documents loaded, dynamic elements of websites visited.

Recommended starting configuration:

  • Recent 16 core CPU with 2.4GHz or better
  • 32 GB RAM
  • Gigabit Ethernet or fiber channel Network
  • SSD with 100 GB

Supports approximately 30 concurrent rendering sessions.

The rendering service is delivered as a docker image and requires a docker environment to be deployed on.

The Unblu Server must be able to communicate with the rendering service via SSH protocol.

The rendering service must be able to communicate with the Collaboration Server using the HTTP(S) protocol.

Note: Either no proxy must be between these two servers, or the proxy must be transparent.

Video Chat

The video chat feature is built on the tokbox cloud service. This may seem like a problem for financial institutions who prefer everything to sit behind their own firewalls. However, using the tokbox cloud service is no different, in principle, from making a telephone call through a provider. For requirements see:

Database Server Hardware Requirements

See Database Server Hardware Requirements for 'suggested' hardware requirements.

Mobile SDK Requirements

See Mobile SDK Requirements

The WAR File

Universal and Document Co-browsing (Optional)

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