Question:
All hosts on Zabbix (monitored by zabbix proxy) simultaneously trigger "zabbix agentd did not get data" (nodata(/xxx/agent.ping,10m)=1) alarm.

Investigation process:
1. Alarm Zabbix history syncer processes more than 75% busy is generated at "2023-09-21 14:42:14". The recovery time is "2023-09-21 14:54:14".
2. At 14:44:36 on 2023-09-21, all hosts on Zabbix (monitored by zabbix proxy) simultaneously trigger "zabbix agentd did not get data" (nodata(/xxx/agent.ping,10m)=1) alarm. The recovery time is "2023-09-21 14:36:38". The duration is "-7m 58s".
2. Check the agent.ping data and find that the alarm time range data is not interrupted.
3. The Zabbix Server log indicates that the Zabbix Server service restarts automatically at 14:33 on 2023-09-21