Linux下分区详解之--Fdisk
作者：吴伟龙
1、 通过Fdisk查看系统分区详细信息：
Fdisk –l 详解：
[root@jetsenLin ~]# fdisk -l
Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
注释：这个硬盘的大小是10.7GB，有255个磁面，63个扇区，1305磁柱(cylinders)
每个cylinder（磁柱）的容量是 8225280 bytes=8225.280 K（约为）=8.225280M（约为）；
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 1305 10377990 8e Linux LVM
id和System 表示的是一个意思，id看起来不太直观，我们要在fdisk 一个分区时，通过指定id来确认分区类型；比如 7表示的就NTFS 分区；这个在fdisk 中要通过t功能来指定。下面的部分会提到；
Disk /dev/sdb: 21.4 GB,21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Disk /dev/sdb doesn't contain a validpartition table
说明：硬盘分区的表示：在Linux 是通过hd*x 或 sd*x 表示的：
其中* 表示的是a、b、c ... ...
另外x 表示的数字 1、2、3 ... ...
hd大多是IDE硬盘；sd大多是SCSI或移动存储；引导（Boot）：表示引导分区，在上面的例子中sda1 是引导分区；
Start （开始）：表示的一个分区从Xcylinder（磁柱）开始；
End （结束）：表示一个分区到 Ycylinder（磁柱）结束；
2、 学会使用fdisk帮助功能：
[root@jetsenLin~]# fdisk /dev/sda
Thenumber of cylinders for this disk is set to 1305.
There isnothing wrong with that, but this is larger than 1024,
and couldin certain setups cause problems with:
1) softwarethat 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): m ---输出帮助信息
Commandaction
a toggle a bootable flag ---设置启动分区
b edit bsd disklabel ---编辑分区标签
c toggle the dos compatibility flag
d delete a partition --删除一个分区
l list known partition types --列出分区类型
m print this menu --帮助
n add a new partition --建立一个新的分区
o create a new empty DOS partition table --创建一个新的空白DOS分区表
p print the partition table ---打印分区表
q quit without saving changes ---退出不保存设置
s createa new empty Sun disklabel ---
t changea partition's system id ---改变分区的ID
u changedisplay/entry units ---改变显示的单位
v verifythe partition table ---检查验证分区表
w write table to disk and exit ---保存分区表
x extra functionality (experts only)
Command (m for help):
3、 通过Fdisk对磁盘分区进行操作：
Fdisk 创建分区：
[root@jetsenLin ~]#fdisk /dev/sdb
Device contains neither a valid DOSpartition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes willremain in memory only,
until you decide to write them. After that,of course, the previous
content won't be recoverable.
The number of cylinders for this disk isset to 2610.
There is nothing wrong with that, but thisis larger than 1024,
and could in certain setups cause problemswith:
1) software that runs at boot time (e.g.,old versions of LILO)
2) booting and partitioning software fromother OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partitiontable 4 will be corrected by w(rite)
Command (m for help): n ---输入m会有帮助信息出来，输入n不打印帮助信息
Command action
e extended
p primary partition (1-4) ---指定分区类型 e为扩展分区 p为主分区
p
Partition number (1-4): 1 ---定义分区数量 --主分区最多只能有四个
First cylinder (1-2610, default 1): 1 ---设定起始分区的位置
Last cylinder or +size or +sizeM or +sizeK(1-2610, default 2610):
Using default value 2610 ---设定结束分区的位置
Command (m for help): w ---保存刚才的配置信息。
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@jetsenLin ~]#
Fdisk 删除分区：
[root@jetsenLin ~]# fdisk /dev/sdb
The number of cylinders for this disk isset to 2610.
There is nothing wrong with that, but thisis larger than 1024,
and could in certain setups cause problemswith:
1) software that runs at boot time (e.g.,old versions of LILO)
2) booting and partitioning software fromother OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): d ---d 是代表删除，并且会列出当前磁盘的分区数。
Selected partition 1
Command (m for help): p ----p 是代表删除后，显示磁盘还有几个剩余的分区。
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Device Boot Start End Blocks Id System ----已经没有分区了
Command (m for help): w ----保存刚才的操作并且生效
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition tablefailed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the nextreboot.
这里报了一错误，分区表正在使用，删除再下次启动生效
Syncing disks. ---同步新的磁盘信息
[root@jetsenLin ~]# fdisk -l /dev/sdb
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Device Boot Start End Blocks Id System
通过fdisk 命令来创建一指定大小的分区并增加一个分区
Fdisk n
创建分区:
[root@jetsenLin ~]# fdisk /dev/sdb
The number of cylinders for this disk isset to 2610.
There is nothing wrong with that, but thisis larger than 1024,
and could in certain setups cause problemswith:
1) software that runs at boot time (e.g.,old versions of LILO)
2) booting and partitioning software fromother OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): n ---创建分区
Command action
e extended
p primary partition (1-4) --指定分区类型为主分区
p
Partition number (1-4): 1 --指定其实分区号
First cylinder (1-2610, default 1): 1 --指定起始柱面号
Last cylinder or +size or +sizeM or +sizeK(1-2610, default 2610): 1024 ---指定终止柱面号
Command (m for help): w ---保存分区配置信息
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition tablefailed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the nextreboot.
Syncing disks.
增加分区:
[root@jetsenLin ~]# fdisk /dev/sdb -----增加分区
The number of cylinders for this disk isset to 2610.
There is nothing wrong with that, but thisis larger than 1024,
and could in certain setups cause problemswith:
1) software that runs at boot time (e.g.,old versions of LILO)
2) booting and partitioning software fromother OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): n ---分区类型
Command action
e extended
p primary partition (1-4) ---还是指定主分区
p
Partition number (1-4): 1 ---分区号，我指定1。
Partition 1is already defined. Delete it beforere-adding it.
–提示分区号1已经存在，删除后操作
Command (m for help): n --我们重新创建分区
Command action
e extended
p primary partition (1-4) --指定分区类型
p
Partition number (1-4): 2 ---因为分区1已经存在，所以我们指定分区2，可通过。
First cylinder (1025-2610, default 1025): ---指定起始礠柱号，默认是上一分区后一号。
Using default value 1025
Last cylinder or +size or +sizeM or +sizeK(1025-2610, default 2610): 2000 --指定终止礠柱号。
Command (m for help): w ---保存分区配置
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition tablefailed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the nextreboot.
Syncing disks.
[root@jetsenLin ~]#
通过fdisk命令来来修改现有分区类型
Fdisk 通过t参数来指定
查看分区类型
[root@jetsenLin ~]# fdisk -l /dev/sdb 查看分区信息，类型是Linux，id是83
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 1024 8225248+ 83 Linux
/dev/sdb2 1025 2000 7839720 83 Linux
修改分区类型
[root@jetsenLin ~]# fdisk /dev/sdb
The number of cylinders for this disk isset to 2610.
There is nothing wrong with that, but thisis larger than 1024,
and could in certain setups cause problemswith:
1) software that runs at boot time (e.g.,old versions of LILO)
2) booting and partitioning software fromother OSs
(e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): t ---进入修改分区类型
Partition number (1-4): 1 ---指定需要修改的分区号
Hex code (type L tolist codes): 6 ---指定分区号为6，也就是FAT16
注意：查看分区类型的代码，在这里可以输入L查看就可以了
Changed system type of partition 1 to 6(FAT16)
Command (m for help): w ---保存
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition tablefailed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the nextreboot.
WARNING: If you have created or modifiedany DOS 6.x
partitions, please see the fdisk manualpage for additional
information.
Syncing disks.
[root@jetsenLin ~]# fdisk -l /dev/sdb ---我们看到已经FAT16，并且ID也改成6了。
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 1024 8225248+ 6 FAT16
/dev/sdb2 1025 2000 7839720 83 Linux
[root@jetsenLin ~]#
4、 对分区进行格式化及加载：
对分区进行格式化的命令如下等，mkfs后面所接的代表的是将要格式化成的文件系统类型：
mkfs.bfs
mkfs.ext2
mkfs.ext3
mkfs.jfs
mkfs.msdos
mkfs.vfat
mkfs.cramfs
mkfs.minix
mkfs.reiserfs
mkfs.xfs
格式化分区：
[root@jetsenLin ~]# mkfs.ext4 /dev/sdb1 ---格式化分区类型为ext4
mke4fs 1.41.5(23-Apr-2009)
Filesystem label= ---我们没有指定卷标，就没有
OS type: Linux ---操作系统类型
Block size=4096 (log=2) --单个块的大小
Fragment size=4096 (log=2) --片大小
1310720 inodes, 5241198blocks
262059 blocks (5.00%)reserved for the super user
First data block=0
Maximum filesystem blocks=0
160 block groups
32768 blocks per group, 32768fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912,819200, 884736, 1605632, 2654208,
4096000
Writing inode tables:done
Creating journal (32768blocks): done
Writing superblocks andfilesystem accounting information: done
This filesystem will beautomatically checked every 27 mounts or
180 days, whichever comesfirst. Use tune4fs -c or -i to override.
挂载磁盘：（临时挂载）
[root@jetsenLin ~]# mkdir/data --创建挂载目录点
[root@jetsenLin ~]#mount /dev/sdb1 /data --将/dev/sdb1 挂载到/data
验证是否成功挂载
[root@jetsenLin ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
7.7G 3.1G 4.2G 43% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 506M 0 506M 0% /dev/shm
/dev/sdb1 20G 16K 20G 1% /data --我们看到已经成功挂载了。
[root@jetsenLin ~]#
挂载磁盘：（永久挂载）
通过vi编辑器编辑/etc/fstab文件，内容如下，（红色部分是刚添加上去的）：
挂载路径 挂载的分区 文件系统 挂载参数 是否要备份 自检顺序
/dev/VolGroup00/LogVol00/ ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
proc /proc proc defaults 0 0
/dev/VolGroup00/LogVol01swap swap defaults 0 0
/data /dev/sdb1 ext4 default 0 0
第四列挂载参数：通过查看man mount 来查看
第五列是否要备份：（0为不备份，1为要备份，一般情况下不用做备份）
第六列自检程序 （0为不自检，1或2为要自检，如果是根分区要设置1，其它分区只能是2）
