centos 建立swap交换缓存区

选择想在哪个分区那个目录下建立分区文件 如下命令则是/home/swap 建一个2G的分区文件

[root@mycentos home]# dd if=/dev/zero of=/home/swap bs=1024 count=2097152 

2097152+0 records in
2097152+0 records out

2147483648 bytes (2.1 GB) copied, 6.21171 s, 346 MB/s

建完后看看

[root@household home]# df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/vda1       25778848 3858808  20609384  16% /

tmpfs             509984       0    509984   0% /dev/shm

格式化新建的分区

[root@household home]# mkswap /home/swap
mkswap: /home/swap: warning: don't erase bootbits sectors
        on whole disk. Use -f to force.
Setting up swapspace version 1, size = 2097148 KiB

no label, UUID=a5d0f1f5-539b-4851-bba6-dc5c49356a45

把新建的分区变成swap分区

[root@household home]# swapon /home/swap

OK！

注:关闭SWAP分区命令为：#  swapoff /home/swap

[root@household home]# free -m
             total       used       free     shared    buffers     cached
Mem:           996        934         61          0          1        518
-/+ buffers/cache:        415        580

Swap:         2047          0       2047

开机自动挂载swap

[root@household home]# echo "/home/swap swap swap defaults  0 0" >> /etc/fstab