zabbix 设置告警邮件key值出现*UNKNOWN*的问题？

问题：

Configuration--> Actions-->action编辑内容如下：

Trigger severity: {TRIGGER.SEVERITY} 

Latest value: {{HOST.HOST}:{ITEM.KEY}.last(0)} 

MAX for 15 minutes: {{HOST.HOST}:{ITEM.KEY}.max(900)}  

MIN  for 15 minutes: {{HOST.HOST}:{ITEM.KEY}.min(900)}  

Event date: {EVENT.DATE}-{EVENT.TIME}   



[------Other information-------] 

[******CPU******] 

CPU load: {{HOST.HOST}:system.cpu.load[all,avg1].last(0)} 

CPU iowait percent: {{HOST.HOST}:system.cpu.util[,iowait].last(0)} 

CPU idle    percent: {{HOST.HOST}:system.cpu.util[,idle].last(0)} 

[******Memory******] 

Memory total: {{HOST.HOST}:vm.memory.size[total].last(0)} 

Memory  available Percent: {{HOST.HOST}:vm.memory.size[pavailable].last(0)} 

[******DISK******] 

Disk Total Space : {{HOST.HOST}:vfs.fs.size[/,total].last(0)} 

Disk Free Space Percent: {{HOST.HOST}:vfs.fs.size[/,pfree].last(0)} 


Trigger URL: {TRIGGER.URL}

收到告警邮件：

Trigger severity: Warning 
Latest value: 3 
MAX for 15 minutes: 3 
MIN for 15 minutes: 1 
Event date: 2014.09.04-14:38:34 

[------Other information-------] 
[******CPU******] 
CPU load: *UNKNOWN* 
CPU iowait percent: 0.79 % 
CPU idle percent: 91.23 % 
[******Memory******] 
Memory total: 3.74 GB 
Memory available Percent: *UNKNOWN* 
[******DISK******] 
Disk Total Space : 14.46 GB 
Disk Free Space Percent: 82.21 % 
Trigger URL:

对出现*UNKNOWN*的key值测试可以取到值：

[root@localhost ~]# zabbix_get -s 192.168.136.130 -k system.cpu.load[all,avg1]
0.050000

解决办法:

      未解决。