Linux 增加 swap 分区

1. 检查当前swap分区

[root@localhost ~]# free -g
             total       used       free     shared    buffers     cached
Mem:            15          0         14          0          0          0
-/+ buffers/cache:          0         15
Swap:            0          0          0

2. 增加交换分区文件及大小

检查没有swap,需要增加。

[root@localhost /]# mkdir swap
[root@localhost /]# cd swap/
[root@localhost swap]# ls
[root@localhost swap]# dd if=/dev/zero of=swapfile bs=4k count=1000000
记录了1000000+0 的读入
记录了1000000+0 的写出
4096000000字节(4.1 GB)已复制，4.36106 秒，939 MB/秒
[root@localhost swap]# mkswap swapfile
mkswap: swapfile: warning: don't erase bootbits sectors
        on whole disk. Use -f to force.
Setting up swapspace version 1, size = 3999996 KiB
no label, UUID=fabcfe27-add9-418a-9666-c5b5d68335f4

3. 启用交换分区

[root@localhost swap]# swapon  swapfile
[root@localhost swap]# free -g
             total       used       free     shared    buffers     cached
Mem:            15          9          5          0          0          8
-/+ buffers/cache:          0         14
Swap:            3          0          3

4. 开机自动挂载

[root@localhost swap]# vim /etc/fstab
	/swap/swapfile  swap  swap defaults 0 0
[root@localhost swap]# mount -a
[root@localhost swap]# free -g
             total       used       free     shared    buffers     cached
Mem:            15          9          5          0          0          8
-/+ buffers/cache:          0         14
Swap:            3          0          3