Server requirements

The install script and infrastructure components support the following base platform requirements:

• One of the following Ubuntu LTS Server versions

  • 24.04

  • 22.04

  • 20.04

  • 18.04

• 2GB memory (minimum)

• 10GB disk (minimum)

• Chip architecture: X86 or Arm

For production systems, disk requirements are usually much higher, especially when capturing images and video.

Small

Small single server

The minimum server configuration is:

• 1 CPU

• 2GB memory

• 10GB disk

You will almost certainly need more disk for a production system, especially if you are capturing images and video. Apart from disk, this small server is adequate for most organisations using Smap for M&E.

In postgresql.conf:

Max connections:  400

In /var/lib/tomcat[x]/conf/context.xml:

MaxActive for survey_definitions and results resources:  60

In /etc/default/tomcat[x]:

JAVA_OPTS="-Djava.awt.headless=true -Xms512m -Xmx768m"

For Ubuntu 24.04+, update setenv.sh in /usr/share/tomcat9/bin to include:

export JAVA_OPTS="-Djava.awt.headless=true -Xms512m -Xmx768m"

Medium

A common vertical scaling step is to add one CPU and more memory:

* 2 CPUs
* 4GB memory
* 100GB disk

You can keep applying this vertical scaling as required. However, at some point, performance is usually better with the database on a separate server, and availability is higher with multiple application servers behind a load balancer. This approach is covered in the large configuration below.

In postgresql.conf:

Max connections:  600

In /var/lib/tomcat[x]/conf/context.xml:

MaxActive for survey_definitions and results resources:  100

In /etc/default/tomcat[x] or setenv.sh (for Ubuntu 24.04+):

JAVA_OPTS="-Djava.awt.headless=true -Xms2048m -Xmx2048m"

Large

A large configuration

The actual configuration (number of servers, server size, and storage choice) varies by deployment. The diagram shows AWS S3 for storage and AWS RDS for the database. Other installations use Azure Blob Storage.

If you are vertically scaling to a large single server (8GB RAM baseline), use the following starting settings. For a multi-server large deployment, apply these values per application server (8GB RAM per server).

In postgresql.conf:

Max connections:  800

In /var/lib/tomcat[x]/conf/context.xml:

MaxActive for survey_definitions and results resources:  120

In /etc/default/tomcat[x] or setenv.sh (for Ubuntu 24.04+):

JAVA_OPTS="-Djava.awt.headless=true -Xms4096m -Xmx4096m"

Configuring for a remote database

1. Add export DBHOST={remote database address} to /etc/environment.

2. Find Tomcat's context.xml file. It should be at /etc/tomcat[version]/context.xml or /var/lib/tomcat9/conf/context.xml. Set the URL for both data sources to match your remote database.

3. Re-run deploy.sh.

Sample /etc/environment:

export DBHOST=remote_db_server.myorg.com

Sample URL for a resource in context.xml:

url="jdbc:postgresql://remote_db_server.myorg.com:5432/survey_definitions"

Configuring a second application server

If you are using a remote database, you can add additional application servers for redundancy and performance. However, currently only one server can run the subscriber batch job that applies submissions to the database. Otherwise, many false update errors will be reported when multiple subscribers clash.

For all but one application server, set this in /etc/environment:

SUBSCRIBER=no

Set this before installing Smap on the new application server.

Apache2 configuration

Apache uses the mpm_event module. Its configuration is in /etc/apache2/mods-available/mpm_event.conf. Modify as required, then restart Apache2. The most important parameter is usually MaxRequestWorkers.

Example mpm_event.conf file for a high volume server:

StartServers            4
ServerLimit             30
MinSpareThreads         50
MaxSpareThreads         75
ThreadLimit             64
ThreadsPerChild         25
MaxRequestWorkers       600
MaxConnectionsPerChild  0

Tomcat configuration