linux开启swap（磁盘缓存）操作

由于工作需要，要帮助同事查看linux服务器的缓存开启情况，经过查找资料，可确定通过以下方法确定Linux磁盘缓存是否已开启。


1.命令行下执行free命令，当显示如下红框内的信息（swap）时，说明swap处于启用状态



此时注意，开启时total和free处均有值。

2.命令行下执行swapoff -a，关闭swap


3.此时执行free命令



此时注意，并闭时total和free处均为0，由此可知swap已经关闭。

4.附swapon、swapoff参数说明

swapon

Usage:
 swapon -a [-e] [-v] [-f]             enable all swaps from /etc/fstab
 swapon [-p priority] [-v] [-f]   enable given swap
 swapon -s                            display swap usage summary
 swapon -h                            display help
 swapon -V                            display version

The parameter:
 {-L label | LABEL=label}             LABEL of device to be used
 {-U uuid  | UUID=uuid}               UUID of device to be used
                              name of device to be used
                                name of file to be used


swapoff

Usage:
 swapoff -a [-v]                      disable all swaps
 swapoff [-v]                disable given swap
 swapoff -h                           display help
 swapoff -V                           display version

The parameter:
 {-L label | LABEL=label}             LABEL of device to be used
 {-U uuid  | UUID=uuid}               UUID of device to be used
                              name of device to be used
                                name of file to be used