要求：監控（本地主機）磁碟使用情況並郵件報警

分析：

1. 任何一個分割槽使用到80%就傳送一個郵件幾個人通知提醒他們磁碟的使用情況；
2. 任何一個分割槽使用到90%以上就在郵件主題給出警告(warning)；
3. Linux伺服器上傳送郵件程式我們使用sendmail。

解答：

第1步： 安裝並啟動sendmail服務並測試

[[email protected] ~]# yum install -y sendmail  mailx
[[email protected] ~]# /bin/systemctl stop sendmail.service 
[
 
[email protected] ~]# ps -ef |grep sendmail
[[email protected] ~]# netstat -lntup |grep 25
[[email protected] ~]# lsof -i:25
[[email protected] ~]# echo "This is test mail" | mail -s 'Test mail' [email protected]

第2步：測試檢視磁碟使用情況的命令

方法1：

[[email protected] ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/xvda1       40G   13G   26G  33% /
devtmpfs        1.9G     0  1.9G   0% /dev
tmpfs           1.8G     0  1.8G   0% /dev/shm
tmpfs           1.8G  428K  1.8G   1% /run
tmpfs           1.8G     0  1.8G   0% /sys/fs/cgroup
tmpfs           354M     0  354M   0% /run/user/0
tmpfs           354M     0  354M   0% /run/user/1004
[
 
[email protected] ~]# df -h|grep -o [0-9]*%
%
33%
0%
0%
1%
0%
0%
0%
[[email protected] ~]# df -h|grep -o [0-9]*%|grep -o '[0-9]\+'
33
0
0
1
0
0
0

方法2：

[[email protected]  ~]# df
Filesystem     1K-blocks     Used Available Use% Mounted on
/dev/xvda1      41152832 12756544  26299188  33% /
devtmpfs         1931300        0   1931300   0% /dev
tmpfs            1809252        0   1809252   0% /dev/shm
tmpfs            1809252      456   1808796   1% /run
tmpfs            1809252        0   1809252   0% /sys/fs/cgroup
tmpfs             361852        0    361852   0% /run/user/0
tmpfs             361852        0    361852   0% /run/user/1004

[
 
[email protected] ~]# df |sed 1d
/dev/xvda1      41152832 12756476  26299256  33% /
devtmpfs         1931300        0   1931300   0% /dev
tmpfs            1809252        0   1809252   0% /dev/shm
tmpfs            1809252      456   1808796   1% /run
tmpfs            1809252        0   1809252   0% /sys/fs/cgroup
tmpfs             361852        0    361852   0% /run/user/0
tmpfs             361852        0    361852   0% /run/user/1004
[[email protected] ~]# df |sed 1d | awk '{print $1,$5}'
/dev/xvda1 33%
devtmpfs 0%
tmpfs 0%
tmpfs 1%
tmpfs 0%
tmpfs 0%
tmpfs 0%
[[email protected] ~]# df |sed 1d | awk '{print $1,$5}'|tr -d %[[email protected] ~]# df -TPh
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/xvda1     ext3       40G   13G   26G  33% /
devtmpfs       devtmpfs  1.9G     0  1.9G   0% /dev
tmpfs          tmpfs     1.8G     0  1.8G   0% /dev/shm
tmpfs          tmpfs     1.8G  456K  1.8G   1% /run
tmpfs          tmpfs     1.8G     0  1.8G   0% /sys/fs/cgroup
tmpfs          tmpfs     354M     0  354M   0% /run/user/0
tmpfs          tmpfs     354M     0  354M   0% /run/user/1004
[[email protected] ~]# df -TPh|awk '{print $6}'
Use%
33%
0%
0%
1%
0%
0%
0%
[[email protected] ~]# df -TPh|awk '{print +$6}'
0
33
0
0
1
0
0
0

方法3：

[[email protected] ~]# df -TPh
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/xvda1     ext3       40G   13G   26G  33% /
devtmpfs       devtmpfs  1.9G     0  1.9G   0% /dev
tmpfs          tmpfs     1.8G     0  1.8G   0% /dev/shm
tmpfs          tmpfs     1.8G  456K  1.8G   1% /run
tmpfs          tmpfs     1.8G     0  1.8G   0% /sys/fs/cgroup
tmpfs          tmpfs     354M     0  354M   0% /run/user/0
tmpfs          tmpfs     354M     0  354M   0% /run/user/1004
[[email protected] ~]# df -TPh|awk '{print $6}'
Use%
33%
0%
0%
1%
0%
0%
0%
[[email protected] ~]# df -TPh|awk '{print +$6}'
0
33
0
0
1
0
0
0
#注意$6前的+號，使用算術運算子進行操作時，運算元自動轉換為數值

方法4：

[[email protected] ~]# df -Th
Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/xvda1     ext3       40G   13G   26G  33% /
devtmpfs       devtmpfs  1.9G     0  1.9G   0% /dev
tmpfs          tmpfs     1.8G     0  1.8G   0% /dev/shm
tmpfs          tmpfs     1.8G  456K  1.8G   1% /run
tmpfs          tmpfs     1.8G     0  1.8G   0% /sys/fs/cgroup
tmpfs          tmpfs     354M     0  354M   0% /run/user/0
tmpfs          tmpfs     354M     0  354M   0% /run/user/1004
[[email protected] ~]# df -Th|awk -F '[ |%]+' 'NR>1 { print $1 " " $6}'
/dev/xvda1 33
devtmpfs 0
tmpfs 0
tmpfs 1
tmpfs 0
tmpfs 0
tmpfs 0

第3步：編寫監控指令碼

#!/bin/sh
source /etc/profile

#define variable
usedList=`df -h|grep -o [0-9]*%|grep -o '[0-9]\+'`
emailArray=('[email protected]'  '[email protected]')
happenTime=`date  "+%Y-%m-%d  %H:%M:%S" `

for i in ${usedList}
do
	if [ ${i} -ge 80 -a ${i} -le 90 ];then

		for email in ${emailArray[*]}
		do
			echo "NOTICE: Disk space for your server, already used ${i}%, ${happenTime} " | mail -s 'Disk Space Notice'  ${email}
		done
		
	elif [ ${i} -gt  90 ];then
	
		for email in ${emailArray[*]}
		do
			echo "WARNING: Low disk space for your server, already used ${i}%, ${happenTime} " | mail -s 'Disk Space Warning'  ${email}
		done
	
    fi
		
done