新建swap分区的规划、挂载和自动挂载示例

注：来自Linux系统管理_磁盘分区和格式化的扩展

Linux系统管理_磁盘分区和格式化：http://murongqingqqq.blog.51cto.com/2902694/1361918

思路：

第一步：首先查看当前swap分区的大小：free -m

第二步：新建磁盘分区指定状态为82，即为swap分区格式：fdisk命令

第三步：重读磁盘分区：partprobe命令

第四步：格式化swap分区：mkswap命令

第五步：手动挂载和卸载swap分区：swapon/off

第六步：设置开机自动挂载swap分区：swapon -a

具体操作：

第一步：首先查看当前swap分区的大小：free -m

[root@localhost ~]# free -m

            total       used       free     shared    buffers     cached

Mem:                                                      

-/+ buffers/cache:                 

Swap:                          

[root@localhost ~]# fdisk -l /dev/sda

Disk /dev/sda: 64.4 GB,  bytes

 heads,  sectors/track,  cylinders

Units = cylinders of  *  =  bytes

  Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *                                Linux

/dev/sda2                               Linux

/dev/sda3                        +    Linux

/dev/sda4                              Extended

/dev/sda5                              Linux swap / Solaris

第二步：新建磁盘分区指定状态为82，即为swap分区格式：fdisk命令

[root@localhost ~]# fdisk /dev/sda

The number of cylinders for this disk is set to .

There is nothing wrong with that, but this is larger than ,

and could in certain setups cause problems with:

) software that runs at boot time (e.g., old versions of LILO)

) booting and partitioning software from other OSs

  (e.g., DOS FDISK, OS/ FDISK)

Command (m for help): n

First cylinder (-, default ):

Using default value 

Last cylinder or +size or +sizeM or +sizeK (-, default ): +1G

Command (m for help): p

Disk /dev/sda: 64.4 GB,  bytes

 heads,  sectors/track,  cylinders

Units = cylinders of  *  =  bytes

  Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *                                Linux

/dev/sda2                               Linux

/dev/sda3                        +    Linux

/dev/sda4                              Extended

/dev/sda5                              Linux swap / Solaris

/dev/sda6                               Linux

Command (m for help): t

Partition number (-): 

Hex code (type L to list codes): 

Changed system type of partition  to  (Linux swap / Solaris)

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error : 设备或资源忙.

The kernel still uses the old table.

The new table will be used at the next reboot.

Syncing disks.

[root@localhost ~]# ls /dev/sd*

/dev/sda  /dev/sda1  /dev/sda2  /dev/sda3  /dev/sda4  /dev/sda5

第三步：重读磁盘分区：partprobe命令

[root@localhost ~]# partprobe

[root@localhost ~]# ls /dev/sd*

/dev/sda  /dev/sda1  /dev/sda2  /dev/sda3  /dev/sda4  /dev/sda5  /dev/sda6

第四步：格式化swap分区：mkswap命令

[root@localhost ~]# mkswap /dev/sda6

Setting up swapspace version , size =  kB

第五步：手动挂载和卸载swap分区：swapon/off

[root@localhost ~]# free -m

            total       used       free     shared    buffers     cached

Mem:                                                      

-/+ buffers/cache:                 

Swap:                          

[root@localhost ~]# swapon /dev/sda6

[root@localhost ~]# free -m

            total       used       free     shared    buffers     cached

Mem:                                                      

-/+ buffers/cache:                

Swap:                          

[root@localhost ~]# swapon -s        //查看都有哪些交换分区挂载

Filename                                Type            Size    Used    Priority

/dev/sda5                               partition               -

/dev/sda6                               partition                -

[root@localhost ~]# swapoff /dev/sda6        //卸载swap分区

[root@localhost ~]# swapon -s

Filename                                Type            Size    Used    Priority

/dev/sda5                               partition               -

第六步：设置开机自动挂载swap分区

[root@localhost ~]# cat /etc/fstab

LABEL=/                 /                       ext3    defaults         

LABEL=/data             /data                   ext3    defaults         

LABEL=/boot             /boot                   ext3    defaults         

tmpfs                   /dev/shm                tmpfs   defaults         

devpts                  /dev/pts                devpts  gid=,mode=   

sysfs                   /sys                    sysfs   defaults         

proc                    /proc                   proc    defaults         

LABEL=SWAP-sda5         swap                    swap    defaults         

[root@localhost ~]# vim /etc/fstab        //编辑/etc/fstab文件，增加下面内容

[root@localhost ~]# cat /etc/fstab | grep sda6    //将下面的信息添加到/etc/fstab文件

/dev/sda6               swap                    swap   defaults         

[root@localhost ~]# swapon -s

Filename                                Type            Size    Used    Priority

/dev/sda5                               partition               -

[root@localhost ~]# swapon -a        //用swapon -a来重读/etc/fstab文件，使新swap分区挂载

[root@localhost ~]# swapon -s       //再次用swapon -s查看的时候，新的swap分区sda6成功挂载

Filename                                Type            Size    Used    Priority

/dev/sda5                               partition               -

/dev/sda6                               partition               -

[root@localhost ~]#

扩展：swap分区开机自动挂载的第二种方式：

第一步：修改/etc/rc.d/rc.local文件

第二步：将swapon /dev/sda6写入这个脚本当中，那么开机就可以自动挂载交换分区/dev/sda6了！！！

注：用swapon -a和reboot命令来实现重读/etc/fstab文件，实现开机自动挂载。

普通分区重读/etc/fstab文件的时候用mount -a，swap分区重读/etc/fstab文件的时候，

使用swapon -a