After Zabbix is installed and configured, a moment comes when maintenance tasks become important. In this last chapter, we looked at three important tasks:

• Monitoring Zabbix itself: We covered internal items that allow figuring out how much data the Zabbix server or proxy is receiving, monitoring cache usage, and verifying how busy the internal processes are, how many unsupported items we have, and a few other things.
• Making backups: We discussed the suggested and popular approaches to making backups (and restoring from them, too) of the most important thing in Zabbix—its database.
• Upgrading Zabbix: We found out the differences between minor and major version upgrades, and how the database is automatically patched by the Zabbix server. We also learned about LTS versions, which are supported for three years and for two extra years for critical and security fixes, while the other versions are supported for about one month from when the next version is released.

While talking about upgrades, we also figured out how the compatibility between different Zabbix components works. With minor-level upgrades, it was very easy; all components, including the server, proxy, and agent, are compatible with each other. Let's try to visualize the major upgrade level compatibility matrix:

As a reminder, from the support perspective, the server and proxy should be of the same major version, and they support all older agent versions. Regarding the Zabbix Java gateway, it should  be from the same major version as the server or proxy; although the protocol hasn't changed, there're no official tests done and no support provided for different major versions.

Before performing a major Zabbix version upgrade, make sure to take a database backup.

After dealing with these three major topics, we discussed general suggestions to keep Zabbix performance acceptable, paying extra attention to housekeeper configuration.

We also found out a way to see the changes made to the Zabbix configuration: the audit log. It allows us to see who made what changes to hosts, items, and other entities. We're a bit disappointed to find out this log doesn't actually record all operations, especially those performed through the API.

We concluded with quite a detailed look at the parameters in the server, proxy, and agent configuration files. Is it maybe worth reminding you to pay close attention to the comments in the configuration files themselves?

We'll conclude this book with two appendices, where we'll discuss the steps and methods for Zabbix troubleshooting, as well as ways to interact with and join the Zabbix community.