1. To add the WebUpd8 Oracle Java PPA repository to the Software Sources in Debian, use the following commands:

   echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee /etc/apt/sources.list.d/webupd8team-java.list
   echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu precise main" | tee -a /etc/apt/sources.list.d/webupd8team-java.list
   apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886

2. execute command apt-get update
   1. ignore the error about "public key is not available"
3. execute command apt-get install oracle-java7-installer and answer affirmatively to "Proceed without verification" and all other installation questions
4. execute command ln -s /usr/lib/jvm/java-7-oracle /usr/lib/jvm/default-java to set Oracle's Java as a default Java on the system
5. check if java is properly installed with command java -version

Step 3: Tomcat 7 package installation:

1. execute command apt-get install tomcat7
2. start Tomcat: service tomcat7 start
3. verify that Tomcat is running properly with the command service tomcat7 status
   

1. Create a file pgdg.list in /etc/apt/sources.list.d/ with some text editor: nano /etc/apt/sources.list.d/pgdg.list and add the following line:
   deb http://apt.postgresql.org/pub/repos/apt/ wheezy-pgdg main

2. execute command: wget --quiet -O - http://apt.postgresql.org/pub/repos/apt/ACCC4CF8.asc | sudo apt-key add -

3. execute command apt-get update

4. execute command apt-get install postgresql postgresql-client

5. verify that PostgreSQL is running properly with the command service postgresql status

Anchor
Post Install Steps Post Install Steps

Post Install Steps

After installation tweaking of configuration files is required in order to utilize the installed RAM to the fullest extent. The main consumers of RAM are operating system, PostgreSQL database and Tomcat.

General rule

for distributing memory is to split it in ratio 2:1 between PostgreSQL and Tomcat with 1 GB or more reserved for operating system.

 For instance:

Tweaking PostgreSQL

Tweaking PostgreSQL for best performance is a topic on which many books were written, but the following are some common sense suggestions

. For the curious ones recommended reads (among countless others) are PostgreSQL Optimization Guide

and PostgreSQL Tuning Guide

.

In order to apply following tweaks edit file /etc/postgresql/PG_VERSION_NUMBER/main/postgresql.conf. You will need to restart the PostgreSQL service after done editing with command:

systemctl restart postgresql

. Almost all of the following parameters are commented with carron character (#).

Be aware that if you comment out the parameter that has been changed

, PostgreSQL will revert to the default value.

Tomcat Memory Allocation 

During installation NetVizura automatically allocates memory for Tomcat process. The amount allocated to Tomcat process is calculated according to the formula:

(RAMtotal - 1GB) / 3 but no less than 1GB.

For instance:

However, if you need to tweak Tomcat RAM allocation differently (the example for 2048MB):

1. Edit file /etc/default/tomcat8 (Debian 9) or /etc/default/tomcat9 (Debian 10)

2. Locate JAVA_OPTS environment variable that defines memory and uncomment it if it is commented. This line looks something like the following:
   JAVA_OPTS="${JAVA_OPTS} -Xmx1024m -Xms1024m +UseConcMarkSweepGC"
3. Modify the -Xmx parameter to allocate additional memory to Tomcat. Additionally, set parameter -Xms to the same amount. This should look something like:
   JAVA_OPTS="-Djava.awt.headless=true -Xmx2048M -Xms2048M -XX:+UseConcMarkSweepGC"

Save the file and restart Tomcat: systemctl restart tomcat8 (Debian 9) systemctl restart tomcat9 (Debian 10)

Elasticsearch Memory Optimization

By default, the memory limit for Elasticsearch should be set to 30% of RAM. If you need it to be set to any other value, edit the file: /etc/elasticsearch/jvm.options, and set values -Xms and Xmx to desired size. Then, restart the Elasticsearch and Tomcat services.