Hi,

Today i’m going to upgrade a zabbix 2.4.7 server tot zabbix server 3.0
You can also use the same procedure for a zabbix proxy.

sudo systemctl stop zabbix-server

on the forums of zabbix or github there are very different opinions to backup zabbix.
If zabbix is a VM, I would shut it down and take a snapshot.
Otherwise on a physical machine, take an image of the whole VM.
If this isn’t possible, the following folders are important

dump the database to a file
mysqldump -u root -p zabbix > zabbix.sql

backup necessary config files (don’t forget custom scripts)
sudo cp /etc/zabbix/zabbix_server.conf /opt/zabbix-backup-2-4-7
sudo cp /etc/zabbix/zabbix_proxy.conf /opt/zabbix-proxy-backup-2-4-7
sudo cp /etc/httpd/conf.d/zabbix.conf /opt/zabbix-backup-2-4-7
sudo cp /usr/share/doc/zabbix-* /opt/zabbix-backup-2-4-7
sudo cp /etc/zabbix/externalscripts /opt/zabbix-backup-2-4-7/externalscripts


Remove current repo of zabbix 2.4.* of zabbix
sudo rm -Rf /etc/yum.repos.d/zabbix.repo

add repo zabbix 3.0
sudo rpm -ivh http://repo.zabbix.com/zabbix/3.0/rhel/7/x86_64/zabbix-release-3.0-1.el7.noarch.rpm

upgrade zabbix 3.0 repo
sudo yum upgrade zabbix-server-mysql zabbix-web-mysql zabbix-agent zabbix-proxy

start zabbix 3.0
Zabbix will upgrade the database automatic when started.
sudo systemctl start zabbix-server