Many clients wish to know what the hardware and operating system requirements are for a Delft-FEWS live system. On this page you can find a list of specifications. If you have any question about the list, or you do not see the operating system of your choice: please contact us. This list is not exhaustive.


Operator client

The Operator Client (Gui) is the thick client for end users.

Forecasting Shell Server

The Forecasting Shell Server (FSS) is the server for execution of forecast runs and import tasks. It contains the modelling software and it's operation is controlled by the Master Controller

Master Controller Server

The master controller organises task traffic and scheduling

JMS Server (no longer required in 2017.02 and beyond)

Java Messaging Service (JMS) controls a large part of the communication between the components.

This component can often be installed on the same server as the Master Controller.

For the JMS to function properly, it is strongly recommended that clients and master-controller components synchronise with the same NTP server so that they run with the same clock time.

Central Database

This is the central data repository, linked to the master controller. The live system is known to run with the following database versions:

Delft-FEWS 2017.02 and later require Oracle 12c

Delft-FEWS 2017.02 requires MS SQL Server 2012 or later

Stop using Postgres 9.2 or earlier, please migrate to a newer Postgres version. Binary transfer is more efficient in newer PostgreSQL versions.

This list is not exhaustive, so contact us if you are thinking of using a different database or a different type.


The webserver is an optional server that hosts and distributes the webpages generated by Delft-FEWS. Hardware requirements depend on the intended use.


This is an optional service which allows SOAP clients to interact with and retrieve data from the Delft-FEWS system. Hardware requirements depend on the intended use. In general it is not recommended to have the PiService on the same machine as the master-controller.

Requirements overview


ComponentDescriptionHardware requirementsOperating system / Software requirementsInstances
Operator Client (Gui)

The Delft-FEWS client used by end-users.

client side, normal pc

Screen resolution depends upon the hardware supplied not on the Delft-FEWS software

Windows 7 / 8 / 10, Server 2012(R2), 2016

Linux RedHat Enterprise, CentOS (6.x 64 bit, 7.x 64 bit)

As many as there are clients



Control and distribute configuration via the Master Controller database.

client side, normal pc

Windows 7 / 8, Server 2012(R2), 2016

Linux RedHat Enterprise, CentOS (6.x 64 bit, 7.x 64 bit)

As many as there are application managers
Forecasting Shell Server

Executes forecast models and stores the results in the central database.

Minimum 2 GB RAM and 1 one CPU core per Forecasting Shell Server instance. CPU typically Intel Xeon E5606 2.33 GHz or equivalent. Always reserve 1 CPU core for the OS.

Windows 7 / 8 / 10, Server 2012(R2), 2016

Linux RedHat Enterprise, CentOS (6.x 64 bit, 7.x 64 bit)

Contains modelling software (incl. licenses), OS usually dependent on 3rd party modules and modelling software

recommended minimum 2, add more depending on computational load
Master Controller Server

Dispatches tasks to the Forecasting Shell Servers.

Maintenance of central database.

Synchronisation between master-controllers.

Sends system alerts.


Minimum 1 GB RAM per MC instance. CPU typically Intel Xeon 2.33 GHz or equivalent.

Windows 7 / 8 / 10, Server 2012(R2), 2016

Linux RedHat Enterprise, CentOS (6.x 64 bit, 7.x 64 bit)

Other Unix-like operating systems possible (e.g. HP-UX, Solaris), as long as there is a JDK of the correct version available for the OS. For 2017.01 and before, JBoss 4 / 5 or ActiveMQ are required for the JMS layer.

1 or 2
Central DatabaseCentral data repository

See Database vendor requirements + 8 GB RAM per DB server including 1 MC DB instance and. CPU typically Intel Xeon E5606 2.33 GHz or equivalent. Add 1 GB RAM per extra MC DB instance.

Oracle 10 / 11 / 12 for versions up to Delft-FEWS 2017.01,

Oracle 12c for Delft-FEWS 2017.02 and later

PostgreSQL 9.6

MS SQL Server 2012 / 2014 / 2016

MS SQL Server 2012 or later for Delft-FEWS 2017.02 and later.

The database instance(s) can be a hosted on an existing database server or cluster.

One instance per Master controller
Admin Interface

Super-user monitoring, system control and task scheduling

Minimum 1 GB RAM

Requires internet browser with javascript and session cookies enabled.

2018.02 requires Tomcat 9, Internet Explorer 10 or older is not supported.

2017.02 and before: Apache Tomcat 6 or higher

The web application runs over the Internet, E.g. Internet Explorer, Edge, Firefox, Chrome.

One instance per Master-Controller machine
"NFFS/FEWS" Web Server (optional)For disseminating forecast data and data from other sourcesTypically 1 GB RAM per server instance and CPU Intel Xeon 2.33 GHz or equivalent.Weblogic 11g with an Oracle Database. Weblogic as Application Server .One instance per Master-Controller machine (optional)
PiService (optional)Data access component.Typically 1 GB RAM per server instance and CPU Intel Xeon 2.33 GHz or equivalent.

Apache Tomcat 6 / 7 or later

Preferrably not on the same machine as the master-controller / MQ server.

1 (optional)
JMS ServerMessaging communication between FEWS components

No longer present in 2017.02. Minimum 1 GB RAM per JMS instance. CPU typically Intel Xeon 2.33 GHz or equivalent. Minimum 1GB disk space for cache.

Windows 7 / 8, Server 2012(R2) (32bit, 64bit)

Linux RedHat Enterprise, CentOS (6.x 64 bit, 7.x 64 bit)

One instance per Master controller
Archive Server (optional)

Stores forecast data, performance indicator data and configurations on a longer time scale than in the central FEWS system. For new projects consider using the Deltares Open Archive instead.

No longer supported in 2017.02, please migrate to the open archive. Ample storage space for Archive files

Apache Tomcat 6 / 7 or later

Separate database instance with same requirements as Central Database for Master Controller.

1 (optional)

All activities contribute to resource consumption on a computing box, whether that box is hardware or virtual and Delft-FEWS will consume resources when running.

Scalability, number of servers

The components mentioned above can all be located on one (powerful) server or each on an individual machine, with all possible configurations in between. It is however common practice to separate the Forecasting Shell server from the Master-controller server. When using multiple machines it is essential that all machines have matching clocks. This can be achieved by making use of one and the same ntp server.

A typical configuration is:

Typically in a dual master-controller setup every master-controller has its own machine so that maintenance can take place without offline time.


It is very well possible to deploy the master-controller components / forecasting shells in virtualized environments. The Deltares ICT team has most experience with Delft-FEWS on VMWare VSphere with in-depth knowledge but Delft-FEWS is also known to run on Microsoft Hyper-V. Virtualization of the Delft-FEWS back-end services can generally be done without problems.  Take into account that  (not Delft-FEWS related)  modelling software may have other requirements or limitations with respect to virtualization of the Forecasting Shells. 

Grid computing

FEWS can work with grid computing. Especially when working with heavy computations, e.g. ensemble forecasting or 3d hydraulic computing, this can be an interesting option to explore. It is recommended to contact the Delft-FEWS product management beforehand.

Embedded Java JRE software versions and other dependencies

Before starting to use Oracle JRE packages released after April 2019, please be aware of changes in the Oracle Java License model, see

Our software is known to work with the following OpenJDK alternatives (recommended):

  1. The Amazon OpenJDK distribution
  2. The OpenJDK reference implementation found at NB. The 11.0.2 distribution contains bugs in the OpenJDK 11.0.2 SSL, which are known to occur specifically when setting up SSL encryption in Tomcat for the https database proxy. When SSL is not used, 11.0.2 is functionally usable.

Java JRE versions (from 2018.02)

++++++ provisional text ++++++++
The new client-package of Delft-FEWS 2018.02 (OC/CM/SA/FSS) will contain an 'embedded' jre (java runtime environment) based on OpenJDK 11. Together with the Delft-FEWS binaries, it forms the Delft-FEWS base-build. The java runtime libraries are placed in an operating system specific sub-folder in the well-known Delft-FEWS bin folder. The jre sub-folders are clearly recognizable under /bin/windows/jre or /bin/linux/jre. This jre can be easily replaced by any other open source or commercially supported version of java 11. Since an Operator Client/Stand Alone and in most cases also Forecasting Shell Server run in a controlled (and secured) environment, it is not necessary to have this jre sub-folder replaced, although it is technically feasible.

In two other locations java is required to run a Delft-FEWS client-server system: in Tomcat (for deploying the Admin Interface or Open Archive) and for the Master Controller. These are part of the server-package we distribute to you. Although these jre's are not embedded, they can be treated similarly with respect to replacing them (or not) by another open source version or commercially supported version of java 11. The decision to arrange additional 'support for Java' is up to the end user of Delft-FEWS.

If - at some point in time - crucial (security) fixes are required to the embedded jre in the client-package of Delft-FEWS,  Deltares will distribute a new 'base-build' for 2018.02 (or higher). Since the distribution of this (new) base-build will take place via the database (and is uploaded via the Admin Interface), updating of all FSS and OC machines will be rather simple. The update of the base-build (including updated embedded jre) will then take place automatically and will neither be a large maintenance burden nor very time-consuming.

New table: to be included/finalised

VersionBase-buildOperator Client
Forecasting Shell


2018.02 embeddedopenjdk11.0.2

NB. only the jvm.dll and not the java executable is shipped with the base build. The jre release version is listed in windows\jre\release and linux\jre\release.

Java JRE versions (2017.02 and earlier)

Note that for security reasons, java should never be installed inside a browser. Delft-FEWS should only be using the java JRE in embedded form.

Since 2014.01 Delft-FEWS requires a base-build. This base-build requires a (minimal) jre-version. See the table below. For 2015.01, 2015.02 and 2016.01 with Java JRE 8 upgrades above _100, a new base-build is required.


JRE version

Operator Client /

Forecasting Shell Server /


Master-controller /


Delft-FEWS 2017.02#76073Java JRE 8 update 17232 / 64 bit 64 bit 
64 bit 
Delft-FEWS 2017.01


Java JRE 8 update 131


32 / 64 bit




Delft-FEWS 2016.02#68073Java JRE 8 update 102
Delft-FEWS 2016.01#62571Java JRE 8 update 100+

32 / 64 bit (beta)

#62088Java JRE 8 update 77
Delft-FEWS 2015.02#62545Java JRE 8 update 100+


32 bit  

#57990Java JRE 8 update 45
Delft-FEWS 2015.01#62465Java JRE 8 update 100+
#54888Java JRE 8 update 45
Delft-FEWS 2014.02#50595Java JRE 7 update 71
Delft-FEWS 2013.01 - 2014.01n/aJava JRE 7 update 71
Delft-FEWS before 2013.01n/aJava JRE 6 update 45

Tomcat webcontainer for Admin Interface / PiService / Proxy

When multiple components require one and the same dll (e.g. for Active Directory / kerberos integration), it is requred to run those components in a separate tomcat instance to avoid problems.

Delft-FEWS 2018.02Tomcat 9
Delft-FEWS 2017.02 and beforeTomcat 5, 6, 7, 8, 9

JMS providers and their Java JRE versions (no longer present in 2017.02 onwards)


JRE version

Windows / LinuxRemarks
Delft-FEWS 2017.02No JMS provider required anymore. Direct database access (DDA) is replacing synchronisation via JMS. Https (as supported by JMS) is not supported.
Delft-FEWS 2017.01ActiveMQ 5.14.5Java JRE 8


64 bit

(installation of 32 bit is not recommended)

ActiveMQ 5.14.5 requires JRE 8 (best 64 bit), but may also be used with JRE 7.
Delft-FEWS 2016.02 and olderActiveMQ 5.11.1ActiveMQ 5.11 requires JRE 8 (best 64 bit), but may also be used with JRE 7.
Delft-FEWS 2017.01 and olderJBoss 4 / 5 / 7Java JRE 6 / 7

Does not function with JRE 8. Note that JBoss4 requires a jdbc driver for storing temporary messages.

The JRE version with which this driver is compiled should be compatible with the JRE used for Jboss4.

Windows VC-Redistributables

The Delft-FEWS software contains Windows executables requiring a VC++ Redistributable Package being installed.

ExecutableInstallerDownload location
JavaService.exeMicrosoft Visual C++ 2008 Redistributable Package (x86)
JavaService_x64.exeMicrosoft Visual C++ 2010 Redistributable Package (x64)