内存交换空间的构建
我们知道CPU计算与数据的存储都会使用到内存，使用内存可以大大减少从磁盘读取的时间，但是当物理内存不足时，，就需要暂时将用不到的程序和数据挪到内存交换空间(swap)
作法：
1. 创建分区（fdisk ,文件）2. 格式化为swap3. 启动4. 查看
创建分区
举例
[root@bogon ~]# fdisk /dev/sda
The number of cylinders for this disk is set to 2610.There is nothing wrong with that, but this is larger than 1024,and could in certain setups cause problems with:1) software that runs at boot time (e.g., old versions of LILO)2) booting and partitioning software from other OSs (e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): p
Disk /dev/sda: 21.4 GB, 21474836480 bytes255 heads, 63 sectors/track, 2610 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System/dev/sda1 * 1 13 104391 83 Linux/dev/sda2 14 1288 10241437+ 83 Linux/dev/sda3 1289 1925 5116702+ 83 Linux/dev/sda4 1926 2610 5502262+ 5 Extended/dev/sda5 1926 2052 1020096 82 Linux swap / Solaris/dev/sda6 2053 2115 506016 83 Linux
Command (m for help): tPartition number (1-6): 6Hex code (type L to list codes): 82Changed system type of partition 6 to 82 (Linux swap / Solaris)
Command (m for help): p
Disk /dev/sda: 21.4 GB, 21474836480 bytes255 heads, 63 sectors/track, 2610 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System/dev/sda1 * 1 13 104391 83 Linux/dev/sda2 14 1288 10241437+ 83 Linux/dev/sda3 1289 1925 5116702+ 83 Linux/dev/sda4 1926 2610 5502262+ 5 Extended/dev/sda5 1926 2052 1020096 82 Linux swap / Solaris/dev/sda6 2053 2115 506016 82 Linux swap / Solaris
Command (m for help): wThe partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: 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.part[root@bogon ~]# partprobe
这里需要在进行设置下system ID
格式化
语法：mkswap设备名称
举例
[root@bogon ~]# mkswap /dev/sda6
Setting up swapspace version 1, size = 518156 kB
启动|关闭语法：swapon [-s]设备名称
swapoff设备名称
选项与参数：
-s:查看所有swap文件系统
举例1：启动swap
[root@bogon ~]# swapon /dev/sda6
举例2：查看所有swap
[root@bogon ~]# swapon -sFilename Type Size Used Priority/dev/sda5 partition 1020088 0 -1/dev/sda6 partition 506008 0 -2
查看
语法：free
举例
total used free shared buffers cachedMem: 2074972 1380996 693976 0 106740 1000288-/+ buffers/cache: 273968 1801004Swap: 1526096 0 1526096
可以看到Swap空间增加1526096
经受雨，面对另一个轮回。
