- Q: Zabbix is working correctly, but some/all graphs are not displayed.
A: Refer to the Apache error log for more details. Usually, this is caused by the PHP script memory limit being too low—if that is the case, increase it by setting the memory_limit parameter to a higher value and restarting the web server. Another possible cause is a broken conf/zabbix.conf.php file—verify that it does not have any weird characters, especially at the end of the file.
- Q: Complex views, such as screens with many elements, sometimes fail to load. What could be causing this?
A: Like the previous problem, check that the PHP memory limit has not been exceeded. Additionally, check the PHP script timeout (max_execution_time parameter) and increase it if necessary.
- Q: My graphs have gaps.
A: It's not only graphs—data is missing in the database as well. This problem should be resolved by finding out what causes the data loss. Common reasons for this are:
-
- Network problems: If the network is unreliable, data will be missing.
- An overloaded monitored device: For example, if you have added a switch with many ports and are monitoring several items on each port very often, try increasing the intervals and disabling unneeded items.
- An overloaded Zabbix server: It's usually the database. Check the system load on the Zabbix database server, especially iowait.
- Q: I had Zabbix installed and running, but it is suddenly showing me the installation screen again.
A: Check the accessibility of the conf/zabbix.conf.php file.
- Q: The conf/zabbix.conf.php file is there, but I still see the installation screen.
A: In some distribution packages, the frontend might expect the frontend configuration file to be in /etc/zabbix/web or a similar location. Check the package documentation.
- Q: I am trying to open a large page with many elements, but refresh kicks in before the page even finishes loading. How can I solve this?
A: Increase the refresh period in your user profile. While the page-loading speed won't be improved by that, at least the page will get a chance to load completely.
- Q: The clock on my server is correct, but the frontend shows incorrect times.
A: Check that the time zone is set correctly in the PHP configuration.
- Q: Zabbix server is running, but the frontend claims it is not.
A: This could be caused by multiple factors:
-
- Check the conf/zabbix.conf.php file—the frontend uses the server address and port specified there to query the Zabbix server process.
- Make sure no firewall is blocking connections from the frontend to the Zabbix server.
- Make sure SELinux is not blocking connections from the frontend to the Zabbix server.
- Make sure you have at least one trapper process enabled—they accept frontend connections. It is also possible that there are not enough trappers to service all requests. This is especially likely if the message about the server being unavailable appears only every now and then. Monitor the busy rate of the trapper processes like we did in Chapter 20, Zabbix Maintenance.
- Q: I am having a problem with a frontend that is not listed here.
A: Check the Apache error log and PHP log—these often offer an insight into the cause. Also, go to Administration | Users or User groups and add your user to the Enabled debug mode group. Afterward, all frontend pages will have a small Debug control in the lower-right corner. Clicking on it will show a lot of detail about that specific page, including the exact API and SQL queries that were performed. Debug mode can use more resources—if some frontend pages stop working after enabling debug mode, try disabling it.
- Q: I am sure that my Zabbix server is properly configured, but it still won't start .
A: It could be that SELinux is active. Another issue can also be that coredumps are activated. The Zabbix agent and Zabbix server will not start if encryption is compiled in, as it can cause security issues with sensitive data being written in the coredump.