服务器上进行drop_caches 留出内存使用

#!/bin/bash
 
###清理内存缓存


used=`free -m | awk 'NR==2' | awk '{print $3}'`
free=`free -m | awk 'NR==2' | awk '{print $4}'`


echo "===========================" >> /var/log/mem.log
date >> /var/log/mem.log
echo "Memory usage | [Use：${used}MB][Free：${free}MB]" >> /var/log/mem.log


if [ $free -le 2000 ]
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
fi