Linux-添加swap分区

建立一个普通的Linux分区（主分区、逻辑分区均可）

fdisk /dev/sdb

Command (m for help): p

Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x740e36e3

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63     4194367     2097152+  83  Linux
/dev/sdb2         4194368    16777215     6291424    5  Extended
/dev/sdb5         4194431     8388735     2097152+  83  Linux
/dev/sdb6         8388799    16777215     4194208+  83  Linux

以sdb6为例，可以看到分区的十六进制编码是83，即普通的Linux分区。

修改分区类型的十六进制编码

//t命令：改写分区十六进制编码
Command (m for help): t  
Partition number (1-6): 6

//L命令可以查看不同分区的十六进制编码，交换分区为82
Hex code (type L to list codes): 82
Changed system type of partition 6 to 82 (Linux swap / Solaris)

Command (m for help): p

Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x740e36e3

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1              63     4194367     2097152+  83  Linux
/dev/sdb2         4194368    16777215     6291424    5  Extended
/dev/sdb5         4194431     8388735     2097152+  83  Linux
/dev/sdb6         8388799    16777215     4194208+  82  Linux swap / Solaris

//分区表写入磁盘并退出
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.

Syncing disks.

格式化交换分区

mkswap /dev/sdb6

Setting up swapspace version 1, size = 4194204 KiB
no label, UUID=40eff2c0-3f6b-440e-bc2a-f71d3d5581a7

启用交换分区

swapon /dev/sdb6

查看交换分区加载状态

free

             total       used       free     shared    buffers     cached
Mem:       1030108     160768     869340        264      12040      56188
-/+ buffers/cache:      92540     937568
Swap:      6291352          0    6291352

停用交换分区

swapoff /dev/sdb6

p.s.

不能直接使用mount命令挂载swap分区，因为swap分区是没有挂载点的。

直接修改/etc/fstab配置文件，使系统启动时自动挂载：

/dev/sdb6               swap                    swap    defaults        0 0

//查看交换分区
 swapon -s
Filename                Type        Size    Used    Priority
/dev/sda2                               partition   2097148 0   -1
/dev/sdb6                               partition   4194204 0   -2