检查内存使用情况，当内存可使用等于100时，释放缓存
[root@localhost thy]# cat checkMem.sh
#!/bin/bash
#防止内存溢出问题
used=`free -m | awk 'NR==2' | awk '{print $3}'`
free=`free -m | awk 'NR==2' | awk '{print $4}'`
echo "=======================================" >> /var/log/mem.log
data >> /var/log/mem.log
echo "Memory usage | [Use: ${used}MB][Free: ${free}MB]" >> /var/log/mem.log
if [ $free -le 100 ];then
sync && echo 1 > /proc/sys/vm/drop_caches
sync && echo 2 > /proc/sys/vm/drop_caches
sync && echo 3 > /proc/sys/vm/drop_caches
echo "OK" >> /var/log/mem.log
else
echo "Not required" >> /var/log/mem.log
循环版本
[root@localhost thy]# cat ./clear_buff_cache.sh
#!/bin/bash
USED=`free -m | awk 'NR==2' | awk '{print $3}'`
FREE=`free -m | awk 'NR==2' | awk '{print $4}'`
while true;
do
echo "===========================" >> /var/log/check_buff_cache.log
date >> /var/log/check_buff_cache.log
echo "Memory usage | [Use：${USED}MB][Free：${FREE}MB]" >> /var/log/check_buff_cache.log
if [ $FREE -le 1000 ] ; then
sync && echo 1 > /proc/sys/vm/drop_caches
sync && echo 2 > /proc/sys/vm/drop_caches
sync && echo 3 > /proc/sys/vm/drop_caches
echo "OK" >> /var/log/check_buff_cache.log
else
echo "Not required" >> /var/log/check_buff_cache.log
fi
sleep 300
done
监控内存和磁盘容量，小于给定值时报警
#!/bin/bash
# 实时监控本机内存和硬盘剩余空间，剩余内存小于500M,根分区剩余空间小于1000M时，发送报警邮件给root管理员
# 得到根分区、内存剩余空间
disk_size=$(df / | awk '///{print $4}')
mem_size=$(free | awk '/Mem/{print $4}')
# PS:内存和磁盘提取的空间大小是以kb为单位
while :
do
# 判断内存和磁盘容小于等于给定值时发送报警邮件
if [ $disk_size -le 1024000 -a $mem_size -le 512000 ];
then
mail -s "Warning" root <<EOF
Insufficient resources,资源不足
EOF
fi
done
注意EOF：
[root@VM_0_10_centos shellScript]# ./checkMem.sh
./checkMem.sh: line 18: warning: here-document at line 14 delimited by end-of-file (wanted `EOF')
./checkMem.sh: line 19: syntax error: unexpected end of file
PS：报如上错误是因为脚本中的EOF前面有空格。EOF前后都不应该有空格或其他符号
磁盘报警：
- 磁盘达到80%发送报警邮件
- 发送邮件命令格式
- 多个报警处理
- 把分区信息写入文件
需要配置邮件服务，乐意参考我邮件服务配置博客：https://www.cnblogs.com/HeiDi-BoKe/p/11883323.html
[root@rhel8 shell]# cat auto_disk_warn.sh
#!/bin/bash
# auto monitor disk
# by author tanbaobao 2020/06/12
D_NETWORK_NAME="ens160"
WARN_DATE=`date +"%A %Y年%m月%d日 %H时:%M分:%S秒"`
CURRENT_DIR=`pwd`
echo -e " 33[31m 33[1m"
rm -rf list.txt
LIST=`df -h | grep "^/dev/" >>list.txt`
cat <<EOF
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++ welcom to use auto monitor system +++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
EOF
echo -e " 33[32m------------------------------------------------------------------ 33[0m"
# echo
# sleep 2
while read line
do
IP_ADDR=`ifconfig $D_NETWORK_NAME|grep -w "inet"|awk '{print $2}'`
D_Name=`echo $line|awk '{print $1,$NF"分区"}'`
D_Total=`echo $line|awk '{print $2}'`
D_Avail=`echo $line|awk '{print $4}'`
D_Percent=`echo $line|awk '{print $5}'|sed 's/%//g'`
if [ "$D_Percent" -ge 50 ];then
cat >email.txt <<EOF
***************** Email *****************
通知类型：故障
服务：Disk Monitor
主机：$IP_ADDR
状态：警告
日期/时间：$WARN_DATE
额外信息：
CRITICAL - DISK Monitor: $D_Name Used more than ${D_Percent}%
EOF
echo -e " 33[32mThe $D_Name has been used for moren than ${D_Percent}%,Please Check. 33[0m"
mail -s "$D_Name Warning" qq邮箱@qq.com < $CURRENT_DIR/email.txt
# echo "The $D_Name has been userd for moren than ${D_Percent}%,Please Check."|mail -s "$D_Name Warning" 2360415871@qq.com
fi
done <list.txt
echo -e "
33[32m------------------------------------------------------------ 33[1m"
echo "Done"