Zabbix agent item several errors in log

[Michael0]

I have several errors in the zabbix logfile from the zabbix agent:

Zabbix agent item [proc.num[crond]] on host [host] failed: first network error, wait for 15 seconds

Zabbix agent item [vm.memory.size[free]] on host [host] failed: first network error, wait for 15 seconds

Zabbix agent item [vfs.fs.size[C:,used]] on host [host] failed: first network error, wait for 15 seconds


and for shell scripts also:

item [host:script1.sh] became not supported: timeout while executing a shell script

item [host:script2.sh] became not supported: timeout while executing a shell script

item [host:script1.sh] became supported

item [host:script2.sh] became supported


The logfile is full of such errors, how can this be solved?

In the frontend everything looks fine, no errors or disabled items/hosts etc..

[Pada]

Test those individual items by running the following command-line on the host that you're monitoring: zabbix_agentd -t <key>
eg. zabbix_agentd -t proc.num[crond]

You typically get this kind of issue when the connection between the Zabbix server and the agent is bad. You can also try switching the items from a passive agent type to "Zabbix Agent (active)". If you have poor connection between the Zabbix server and agent, then it may be worth while to install a proxy server on the same network as the Zabbix agent, so that the proxy can cache values for the duration where the connection is poor.
The proxy will fill in the gaps, but unfortunately it won't fix gaps in calculated items.

If your scripts takes too long to execute, then you'll need to fix the script or increase the timeout on the agent/service executing the script.