Set variable Timeout=30 in zabbix_agentd configuration file.

1. time zabbix_agentd -c zabbix.conf -t raid
   raid [t|OK]

real 0m2.961s
user 0m0.052s
sys 0m0.048s

1. time zabbix_agentd -c zabbix.conf -t raid
   Alarm clock

real 0m3.005s
user 0m0.000s
sys 0m0.004s

It seems that variable does not work and alarm is executed after default 3s timeout. In zabbix_agentd daemon mode zabbix_server gets "Timeout while executing a shell script" after this happened.