shell脚本监控系统可用内存

要求：监控系统可用内存,小于100M就发送报警邮件 否则,提示内存充足,定时 任务每3分钟1次

1.取出当前内存

#centos 6.x buffers/cache 这一行 第3行
[root@localhost tmp]# free -h
             total       used       free     shared    buffers     cached
Mem:          980M       167M       812M       224K       8.0M        43M
-/+ buffers/cache:       116M       864M
Swap:         1.0G         0B       1.0G

#centos 7 free+buffer+cache  看available
[root@m01 log]# free -h
              total        used        free      shared  buff/cache   available
Mem:           972M         90M        745M        7.6M        137M        728M
Swap:          767M          0B        767M

2.书写脚本，发邮件

#centos7脚本
#!/bin/bash
mem=$(free -m|awk 'NR==2{print $NF}')
if [ "$mem" -lt "10000" ]
then
  echo "mem is buzu" |tee /root/mem.log
 mail -s "memory is buzu" 841997568@qq.com </root/mem.log
else
  echo "mem is zu"
fi

#centos6脚本
#!/bin/bash
mem=$(free -m|awk 'NR==3{print $4}')
if [ "$mem" -lt "10000" ]
then
  echo "mem is buzu" |tee /root/mem.log
 mail -s "memory is buzu" 841997568@qq.com </root/mem.log
else
  echo "mem is zu"
fi

如果没mail服务会提示报错，直接yum装一个

yum install -y mailx

如何配置mailx发邮件：linux系统使用mail发送邮件配置

3. 定时任务

[root@m01 /server/scripts]# crontab -e
#check memory
3 * * * * sh /server/scripts/chk_mem.sh &>/dev/null