Linux命令：fdisk-MBR磁盘分区

▶ fdisk 磁盘分区

fdisk 是用于对 MBR磁盘 的分区工具，对于 MBR 分区来说最大支持的是2TB容量的磁盘。

fdisk 用于观察硬盘实体的使用情况，也能对硬盘进行分区。

fdisk [options] device

fdisk -l [device...]

▷ fdisk 用于查看磁盘分区的信息

▷▷ fdisk -l 查看

可以直接使用 fdisk -l 设备名 来查看磁盘。

[root@server /]# fdisk -l /dev/nvme0n2
Disk /dev/nvme0n2: 10 GiB, 10737418240 bytes, 20971520 sectors
Disk model: VMware Virtual NVMe Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

▷▷ 在 fdisk 内查看

fdisk本来就是一个交互式的工具。

[root@server /]# fdisk /dev/nvme0n2

Welcome to fdisk (util-linux 2.37.4).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x855a2c8e.

Command (m for help): p
Disk /dev/nvme0n2: 10 GiB, 10737418240 bytes, 20971520 sectors
Disk model: VMware Virtual NVMe Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x855a2c8e

▷ fdisk 对磁盘分区

准备一个磁盘分区

[root@server /]# lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sr0              11:0    1 10.2G  0 rom
nvme0n1         259:0    0   20G  0 disk
├─nvme0n1p1     259:1    0    1G  0 part /boot
└─nvme0n1p2     259:2    0   19G  0 part
  ├─rl_192-root 253:0    0   17G  0 lvm  /
  └─rl_192-swap 253:1    0    2G  0 lvm  [SWAP]
nvme0n2         259:3    0   10G  0 disk

这里对最后一行也就是 neme0n2 这个磁盘设备。

相关的版本：

[root@server /]# fdisk -v
fdisk from util-linux 2.37.4

对 neme0n2 该磁盘进行分区。

[root@server /]# fdisk /dev/nvme0n2

Welcome to fdisk (util-linux 2.37.4).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0xcd91c5d6.

Command (m for help):

创建一个 5G 的磁盘分区。

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-20971519, default 2048):
Last sector, +/-sectors or +/-size{K,M,G,T,P} (2048-20971519, default 20971519): +5G

Created a new partition 1 of type 'Linux' and of size 5 GiB.

查看此时的磁盘分区：

Command (m for help): p
Disk /dev/nvme0n2: 10 GiB, 10737418240 bytes, 20971520 sectors
Disk model: VMware Virtual NVMe Disk
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xcd91c5d6

Device         Boot Start      End  Sectors Size Id Type
/dev/nvme0n2p1       2048 10487807 10485760   5G 83 Linux

此时分区的内容保存在内存上，还没有写入到分区表上。

当完成后要使用 w 进行保存，如果不使用 w 进行保存而直接 q 关闭，磁盘分区的内容就不会写到对应的分区表上。

Command (m for help): w

The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

[root@server /]#

▶ fdisk 交互模式下的其他

▷ m 查看帮助

[root@server /]# fdisk /dev/nvme0n2

Welcome to fdisk (util-linux 2.37.4).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): m

Help:

  DOS (MBR)
   a   toggle a bootable flag
   b   edit nested BSD disklabel
   c   toggle the dos compatibility flag

  Generic
   d   delete a partition
   F   list free unpartitioned space
   l   list known partition types
   n   add a new partition
   p   print the partition table
   t   change a partition type
   v   verify the partition table
   i   print information about a partition

  Misc
   m   print this menu
   u   change display/entry units
   x   extra functionality (experts only)

  Script
   I   load disk layout from sfdisk script file
   O   dump disk layout to sfdisk script file

  Save & Exit
   w   write table to disk and exit
   q   quit without saving changes

  Create a new label
   g   create a new empty GPT partition table
   G   create a new empty SGI (IRIX) partition table
   o   create a new empty DOS partition table
   s   create a new empty Sun partition table

▷ t 改变分区类型

L能显示所有可以改变的分区类型。

Command (m for help): t

Selected partition 1
Hex code or alias (type L to list all): L

00 Empty            24 NEC DOS          81 Minix / old Lin  bf Solaris
01 FAT12            27 Hidden NTFS Win  82 Linux swap / So  c1 DRDOS/sec (FAT-
02 XENIX root       39 Plan 9           83 Linux            c4 DRDOS/sec (FAT-
03 XENIX usr        3c PartitionMagic   84 OS/2 hidden or   c6 DRDOS/sec (FAT-
04 FAT16 <32M       40 Venix 80286      85 Linux extended   c7 Syrinx
05 Extended         41 PPC PReP Boot    86 NTFS volume set  da Non-FS data
06 FAT16            42 SFS              87 NTFS volume set  db CP/M / CTOS / .
07 HPFS/NTFS/exFAT  4d QNX4.x           88 Linux plaintext  de Dell Utility
08 AIX              4e QNX4.x 2nd part  8e Linux LVM        df BootIt
09 AIX bootable     4f QNX4.x 3rd part  93 Amoeba           e1 DOS access
0a OS/2 Boot Manag  50 OnTrack DM       94 Amoeba BBT       e3 DOS R/O
0b W95 FAT32        51 OnTrack DM6 Aux  9f BSD/OS           e4 SpeedStor
0c W95 FAT32 (LBA)  52 CP/M             a0 IBM Thinkpad hi  ea Linux extended
0e W95 FAT16 (LBA)  53 OnTrack DM6 Aux  a5 FreeBSD          eb BeOS fs
0f W95 Ext'd (LBA)  54 OnTrackDM6       a6 OpenBSD          ee GPT
10 OPUS             55 EZ-Drive         a7 NeXTSTEP         ef EFI (FAT-12/16/
11 Hidden FAT12     56 Golden Bow       a8 Darwin UFS       f0 Linux/PA-RISC b
12 Compaq diagnost  5c Priam Edisk      a9 NetBSD           f1 SpeedStor
14 Hidden FAT16 <3  61 SpeedStor        ab Darwin boot      f4 SpeedStor
16 Hidden FAT16     63 GNU HURD or Sys  af HFS / HFS+       f2 DOS secondary
17 Hidden HPFS/NTF  64 Novell Netware   b7 BSDI fs          fb VMware VMFS
18 AST SmartSleep   65 Novell Netware   b8 BSDI swap        fc VMware VMKCORE
1b Hidden W95 FAT3  70 DiskSecure Mult  bb Boot Wizard hid  fd Linux raid auto
1c Hidden W95 FAT3  75 PC/IX            bc Acronis FAT32 L  fe LANstep
1e Hidden W95 FAT1  80 Old Minix        be Solaris boot     ff BBT

Aliases:
   linux          - 83
   swap           - 82
   extended       - 05
   uefi           - EF
   raid           - FD
   lvm            - 8E
   linuxex        - 85
Hex code or alias (type L to list all):

Linux 的是 83，swap 的是 82。

▶ fdisk 参数选项

由于 fdisk 参数用的少，所以放在最后面。

参数	内容
-b <大小>	扇区大小(512、1024、2048或者4096)
-c[=<模式>]	兼容模式：“dos” 或者 “nondos”(默认)
-h	打印此帮助文本
-u[=<单位>]	显示单位 cylinders(柱面) 或 sectors(扇区，默认)
-v	打印程序版本
-C <数字>	指定柱面数字
-H <数字>	指定磁头数
-S <数字>	指定每个磁道的扇区数