In order to check CPU usage on every core, I have created Calculated Item with Forlmula "100-last("system.cpu.util[0,idle,avg1]")" . this is good, but if in period of time zabbix server can not get system.cpu.util[0,idle,avg1] item, the calculated item will be same value until new value is fetched for system.cpu.util[0,idle,avg1], so all calculated items are not true. and related graphs display one line in graph .
if one item is not fetch,correspond calculated items are not calculated. I think this behavior is not true and reasonable.
Anyhow calculated items are important part of monitoring system.
Thanks for any suggestion.