參考網站:http://blog.csdn.net/hshl1214/article/details/6048278
原帖子寫的很好，我把步驟給貼出來，測試系統：rhel6.4 x64
1.新建磁盤分區作爲swap分區
[root@localhost /]# free -m //查看當前swap信息
total used free shared buffers cached
Mem: 1878 348 1530 0 19 156
-/+ buffers/cache: 172 1706
Swap: 4031 0 4031
[root@localhost /]# swapoff -a //停用swap空間
[root@localhost /]# free -m //查看是否停用
total used free shared buffers cached
Mem: 1878 345 1532 0 19 156
-/+ buffers/cache: 169 1709
Swap: 0 0 0
[root@localhost /]# fdisk /dev/sdb //進入sdb硬盤中（sdb硬盤中有多餘未使用的磁盤空間）
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n //新建分區
Command action
e extended
p primary partition (1-4)
p //創建主分區
Partition number (1-4): 2 //sdb硬盤的第二個主分區
First cylinder (8193-10240, default 8193): //從硬盤哪個柱面開始，enter鍵默認（可以寫對應數字）
Using default value 8193
Last cylinder, +cylinders or +size{K,M,G} (8193-10240, default 10240): //從硬盤哪個柱面開始，enter鍵默認
Using default value 10240
Command (m for help): p //查看改變後分區情況，P:打印分區信息
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
64 heads, 32 sectors/track, 10240 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb92c060c
Device Boot Start End Blocks Id System
/dev/sdb1 1 8192 8388592 83 Linux
/dev/sdb2 8193 10240 2097152 83 Linux
Command (m for help): t //開始修改/dev/sdb2的屬性，改爲swap id：82
Partition number (1-4): 2 //選擇要修改的分區
Hex code (type L to list codes): 82 //swap分區Id
Changed system type of partition 2 to 82 (Linux swap / Solaris)
Command (m for help): p //查看改變後分區情況
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
64 heads, 32 sectors/track, 10240 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb92c060c
Device Boot Start End Blocks Id System
/dev/sdb1 1 8192 8388592 83 Linux
/dev/sdb2 8193 10240 2097152 82 Linux swap / Solaris //這裏被改成swap屬性
Command (m for help): w //保存修改
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.
[root@localhost /]# mkswap /dev/sdb2
/dev/sdb2: No such file or directory //修改後需要重啓
[root@localhost /]# reboot //重啓
[root@localhost ~]# fdisk -l
[root@localhost ~]# mkswap /dev/sdb2 //格式化swap分區
Setting up swapspace version 1, size = 2097148 KiB
no label, UUID=2d26d5ad-4ee2-4c1d-b90c-7cf4060fd9a9
[root@localhost ~]# swapon /dev/sdb2 //啓用swap
[root@localhost ~]# free -m // 查看swap容量是否變大，判斷操作是否成功
total used free shared buffers cached
Mem: 1878 348 1529 0 18 156
-/+ buffers/cache: 173 1704
Swap: 6079 0 6079[root@localhost ~]# vi /etc/fstab
/dev/sdb2 swap swap defaults 0 0 //使系統開機時自啓用，在文件最後添加一行
###########################################################
2.用文件作爲Swap分區
(緊隨上面的信息做如下操作）
[root@localhost ~]# free -m //查看初始信息
total used free shared buffers cached
Mem: 1878 348 1529 0 18 156
-/+ buffers/cache: 173 1704
Swap: 6079 0 6079
#創建要作爲swap分區的文件:增加1GB大小的交換分區，則命令寫法如下，其中的count等於想要的塊的數量（bs*count=文件大小）。
[root@localhost ~]# dd if=/dev/zero of=/root/swapfile bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 12.1908 s, 88.1 MB/s
[root@localhost ~]# mkswap /root/swapfile //格式化爲交換分區文件
mkswap: /root/swapfile: warning: don't erase bootbits sectors
on whole disk. Use -f to force.
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=3330e86b-ec5a-4423-bc08-07bcc3785495
[root@localhost ~]# swapon /root/swapfile //啓用交換分區文件
[root@localhost ~]# free -m //查看修改後的信息，判定操作是否成功
total used free shared buffers cached
Mem: 1878 1403 474 0 19 1180
-/+ buffers/cache: 204 1674
Swap: 7103 0 7103
[root@localhost ~]# vi /etc/fstab
/root/swapfile swap swap defaults 0 0 //使系統開機時自啓用，在文件最後添加一行
3.刪除swap空間
[root@localhost ~]# swapoff /root/swapfile
[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 1878 1403 475 0 19 1180
-/+ buffers/cache: 203 1674
Swap: 6079 0 6079
[root@localhost ~]#