清理yum緩存
清理yum緩存使用yum clean 命令蔼水，yum clean 的參數(shù)有headers, packages, metadata, dbcache, plugins, expire-cache, rpmdb, all
yum clean headers #清理/var/cache/yum的headers
yum clean packages #清理/var/cache/yum下的軟件包
yum clean metadata
...
yum clean all #全部清除
Linux釋放內(nèi)存
釋放網(wǎng)頁緩存(To free pagecache):
sync; echo 1 > /proc/sys/vm/drop_caches
釋放目錄項(xiàng)和索引(To free dentries and inodes):
sync; echo 2 > /proc/sys/vm/drop_caches
釋放網(wǎng)頁緩存渣锦，目錄項(xiàng)和索引（To free pagecache, dentries and inodes）:
sync; echo 3 > /proc/sys/vm/drop_caches
下面是我實(shí)際的數(shù)據(jù)。
[root@localhost ~]# free -m #查看內(nèi)存
total used free shared buff/cache available
Mem: 481 224 120 1 136 202
Swap: 1023 283 740
[root@localhost ~]# sync; echo 3 > /proc/sys/vm/drop_caches
[root@localhost ~]# free -m #從120到186伶跷，釋放了66m的內(nèi)存
total used free shared buff/cache available
Mem: 481 209 186 1 85 222
Swap: 1023 283 740
