mkswap命令简介：
用于创建格式化交换分区swap.
1．命令格式：
free 查看系统内存使用情况
-m：以M为单位显示（默认以字节显示）
[root@xuelinux ~]# free
total used free shared buffers cached
Mem: 1938628 161284 1777344 0 26632 57404
-/+ buffers/cache: 77248 1861380
Swap: 2047992 0 2047992
[root@xuelinux ~]# free -m
total used free shared buffers cached
Mem: 1893 157 1735 0 26 56
-/+ buffers/cache: 75 1817
Swap: 1999 0 1999
mkswap disk eg:mkswap /dev/sda
-L LABEL 指定卷标
swapon /devb/sda9 启用交换分区
swapon -a 启用所有的定义在/etc/fstab文件中的交换设备
swapoff /dev/sda9 关闭交换分区
2．命令功能：
对分区进行swap格式化
3．命令参数：
free 查看系统内存使用情况
-m：以M为单位显示（默认以字节显示）
mkswap disk eg:mkswap /dev/sda
-L LABEL 指定卷标
4．命令实例：
如何对swap交换分区进行增加？
[root@xuelinux ~]# fdisk /dev/sda
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 查看硬盘是否有可用未分配的容量及分区信息
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x000f2a2b
Device Boot Start End Blocks Id System
/dev/sda1 * 1 256 2048000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 256 893 5120000 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 893 1403 4096000 83 Linux
/dev/sda4 1403 2611 9706496 5 Extended
/dev/sda5 1403 1786 3072000 83 Linux
/dev/sda6 1786 2041 2048000 82 Linux swap / Solaris
/dev/sda7 2041 2296 2048000 83 Linux
/dev/sda8 2296 2427 1057726 fd Linux raid autodete
Command (m for help): n 新增一个分区
First cylinder (2428-2611, default 2428):
Using default value 2428
Last cylinder, +cylinders or +size{K,M,G} (2428-2611, default 2611): +1G 新增分区大小为1G
Command (m for help): t 修改分区类型
Partition number (1-9): 9 选择需要修改类型的分区
Hex code (type L to list codes): L 查看系统支持的所有分区类型
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c Hidden
Hex code (type L to list codes): 82 选择分区类型为82 swap类型
Changed system type of partition 9 to 82 (Linux swap / Solaris)
Command (m for help): p 查看硬盘是否有可用未分配的容量及分区信息
Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x000f2a2b
Device Boot Start End Blocks Id System
/dev/sda1 * 1 256 2048000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 256 893 5120000 83 Linux
Partition 2 does not end on cylinder boundary.
/dev/sda3 893 1403 4096000 83 Linux
/dev/sda4 1403 2611 9706496 5 Extended
/dev/sda5 1403 1786 3072000 83 Linux
/dev/sda6 1786 2041 2048000 82 Linux swap / Solaris
/dev/sda7 2041 2296 2048000 83 Linux
/dev/sda8 229 2427 1057726 fd Linux raid autodetect
/dev/sda9 2428 2559 1060258+ 82 Linux swap / Solaris 分区已经修改为swap类型
W95 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
Command (m for help): w 保存分区操作并退出
The 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 or after you run partprobe(8) or kpartx(8)
[root@xuelinux ~]# partprobe /dev/sda 通知内核识别刚刚新建的分区
[root@xuelinux ~]# mkswap /dev/sda9 把分区格式化为swap格式
Setting up, swapspace version 1, size=1011671 kB 已经格式化为swap格式
[root@xuelinux ~]# free -m free -m 以MB为单位查看系统内存使用情况
total used free shared buffers cached
Mem: 1893 157 1735 0 26 56
-/+ buffers/cache: 75 1817
Swap: 1999 0 1999 但是此处交换分区swap依旧没有增加
[root@xuelinux ~]# swapon /dev/sda9
[root@xuelinux ~]# free -m free -m 以MB为单位查看系统内存使用情况
total used free shared buffers cached
Mem: 1893 157 1735 0 26 56
-/+ buffers/cache: 75 1817
Swap: 2999 0 2999 此处交换分区swap增加为3G新增了1G
本文转自wang650108151CTO博客，原文链接：http://blog.51cto.com/woyaoxuelinux/1867555 ，如需转载请自行联系原作者
