添加交换分区swap

方法一：新建分区

使用fdisk工具新建一个分区

[root@VM_168_102_centos ~]# fdisk /dev/xvdb 
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xad066822.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

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): p

Disk /dev/xvdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xad066822

    Device Boot      Start         End      Blocks   Id  System

Command (m for help): n        
Command action
   e   extended
   p   primary partition (1-4)
p     
Partition number (1-4): 1
First cylinder (1-1305, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305): +2G

Command (m for help): p

Disk /dev/xvdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xad066822

    Device Boot      Start         End      Blocks   Id  System
/dev/xvdb1               1         262     2104483+  83  Linux

Command (m for help): t #调整分区类型
Selected partition 1
Hex code (type L to list codes): 82
Changed system type of partition 1 to 82 (Linux swap / Solaris)

Command (m for help): p

Disk /dev/xvdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xad066822

    Device Boot      Start         End      Blocks   Id  System
/dev/xvdb1               1         262     2104483+  82  Linux swap / Solaris

将/dev/xvdb1分区格式为交换分区

[root@VM_168_102_centos ~]# mkswap /dev/xvdb1
Setting up swapspace version 1, size = 2104476 KiB
no label, UUID=4bd9be30-3473-4db3-8b3d-0cd930347ba1

挂载交换分区

[root@VM_168_102_centos ~]# swapon /dev/xvdb1
[root@VM_168_102_centos ~]# swapon �Cs 
Filename                Type        Size    Used    Priority
/dev/xvdb1                              partition    2104472    0    -1

卸载交换分区

[root@VM_168_102_centos ~]# swapoff /dev/xvdb1
[root@VM_168_102_centos ~]# free
             total       used       free     shared    buffers     cached
Mem:       1018532     123916     894616          0      14624      41096
-/+ buffers/cache:      68196     950336
Swap:            0          0          0
[root@VM_168_102_centos ~]# swapon -s
Filename                Type        Size    Used    Priority

 

方法二：新建虚拟内存文件

创建1G的空文件

[root@VM_168_102_centos tmp]# dd if=/dev/zero of=/tmp/swap1 bs=1M count=1024 #创建1G的空文件swap1
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 4.66541 s, 230 MB/s

[root@VM_168_102_centos tmp]# ls -lh s* 
-rw-r--r-- 1 root root 1.0G Aug 22 16:01 swap1

将/tmp/swap1格式为交换分区

[root@VM_168_102_centos tmp]# mkswap /tmp/swap1
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=dbbc7b8d-d77e-426d-aa9f-fe1e4204a09e
[root@VM_168_102_centos tmp]# free
             total       used       free     shared    buffers     cached
Mem:       1018532     930276      88256          0      11420     830364
-/+ buffers/cache:      88492     930040
Swap: 0          0          0

挂载交换分区

[root@VM_168_102_centos tmp]# swapon /tmp/swap1
[root@VM_168_102_centos tmp]# swapon -s
Filename                Type        Size    Used    Priority
/tmp/swap1                              file        1048568    0    -1
[root@VM_168_102_centos tmp]# free
             total       used       free     shared    buffers     cached
Mem:       1018532     931516      87016          0      11596     830548
-/+ buffers/cache:      89372     929160
Swap: 1048568          0    1048568

卸载交换分区

[root@VM_168_102_centos tmp]# swapoff /tmp/swap1
[root@VM_168_102_centos tmp]# swapon -s
Filename                Type        Size    Used    Priority
[root@VM_168_102_centos tmp]# free
             total       used       free     shared    buffers     cached
Mem:       1018532     931044      87488          0      11696     830620
-/+ buffers/cache:      88728     929804
Swap: 0          0          0