First of all, I tried out to increase the number of pre-forked instances of pollers for the Zabbix server, that is, I changed its default value from 5 to 256 (remember that for that case, you have to set the the number of maximum connections in MySQL - max_connections - higher than 256, since every single poller opens a dedicated connection to the database).
root@zabbix-server:~# cat /etc/zabbix/zabbix_server.conf ... # StartPollers=5 StartPollers=256 root@zabbix-server:~# cat /etc/mysql/my.cnf ... max_connextions = 512
Below you can see the outcome after applying it (Zabbix server performance).
And the Zabbix data gathering process.
In the first figure, you can observe that the Zabbix queue has gone from 48 to 30 (approximately), and for the second one, the Zabbix busy poller processes went from 100% to 24%. So it is clear that if you have a server with enough resources, there is no problem to start many pollers. These kind of processes are responsible for requesting the data defined in the items, so the more pollers have available, the less overloaded the system is.
Other Zabbix server parameter that you ought to take into account is for example the Timeout (specifies how log pollers wait for agent responses). Try not to assign a very high value. Otherwise, the system might get overloaded.
Next week, I will end up this series of articles by accomplishing the part of the client.