概述
fdisk是一种用于管理磁盘分区的工具，常用于Linux和其他Unix-like操作系统中。它可以用于创建、删除和修改磁盘分区，并支持多种文件系统类型，例如FAT、ext2、ext3等。
fdisk还可以显示当前系统中所有磁盘的分区信息，包括磁盘标识符、分区类型、分区大小等。使用fdisk，用户可以轻松地管理磁盘空间，为不同的操作系统或应用程序分配不同的存储空间。
除此之外，fdisk还支持MBR(Master Boot Record)分区方案，它是一种常见的磁盘分区方案，能够在BIOS引导下启动操作系统。
MBR
MBR（Master Boot Record）分区是指使用MBR分区方案的磁盘分区方式。MBR分区方案是一种常见的分区方案，能够在BIOS引导下启动操作系统。MBR分区方案将磁盘的前512个字节（即MBR）用于存储分区表和引导程序。其中分区表记录了磁盘分区的信息，包括分区类型、分区起始位置、分区大小等。MBR分区方案最多支持4个主分区或3个主分区和1个扩展分区，扩展分区可以划分为多个逻辑分区。MBR分区方案已经存在了很长时间，但是它有一个缺点，即它只支持最大2TB的磁盘容量。如果需要使用更大的磁盘，就需要使用GPT（GUID Partition Table）分区方案。
环境
系统：Rocky Linux release 8.5
工具：fdisk from util-linux 2.32.1
硬盘：虚拟机添加了一块20G的硬盘
实践
主分区
[root@host ~]# lsblk -p // 通过lsblk来查看一下新增的硬盘位置(/dev/sdb)
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
/dev/sr0 11:0 1 1024M 0 rom
[root@host ~]# fdisk /dev/sdb // 使用fdisk工具对/dev/sdb这块硬盘进行分区
Welcome to fdisk (util-linux 2.32.1).
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 0x178d8de5.
Command (m for help): n // 输入n进行新建分区操作
Partition type
p primary (0 primary, 0 extended, 4 free)
e extended (container for logical partitions)
Select (default p): p // p是创建主分区，e是创建逻辑分区
Partition number (1-4, default 1): 1 // 选择分区号,默认为1,这里可以改其他的(MBR分区最多有4个分区)
First sector (2048-41943039, default 2048): // 起始扇区选择默认即可
Last sector, +sectors or +size{K,M,G,T,P} (2048-41943039, default 41943039): +5G //设置分区大小我这里设置5G
Created a new partition 1 of type 'Linux' and of size 5 GiB. //提示创建成功
Command (m for help): p // p查看分区表
Disk /dev/sdb: 20 GiB, 21474836480 bytes, 41943040 sectors
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: 0x178d8de5
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 10487807 10485760 5G 83 Linux // 创建好的分区
Command (m for help): w // 保存之前的分区操作
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
[root@host ~]# mkfs.xfs /dev/sdb1 // 格式化创建好的分区
meta-data=/dev/sdb1 isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=1310720, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@host ~]# mkdir /sdb1 // 创建挂载位置
[root@host ~]# mount /dev/sdb1 /sdb1 // 将格式化好的分区进行挂载
[root@host ~]# lsblk -p // 查看分区情况
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
└─/dev/sdb1 8:17 0 5G 0 part /sdb1 // 已经挂载好可以使用了
/dev/sr0 11:0 1 1024M 0 rom逻辑分区
[root@host ~]# fdisk /dev/sdb // 对/dev/sdb进行分区
Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n // 创建分区
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): e // 创建逻辑分区
Partition number (2-4, default 2): // 分区号
First sector (10487808-41943039, default 10487808): // 设置起始扇区选择默认即可
Last sector, +sectors or +size{K,M,G,T,P} (10487808-41943039, default 41943039): // 设置大小，逻辑分区的默认大小是剩余全部存储空间,这里我选择默认。
Created a new partition 2 of type 'Extended' and of size 15 GiB.
Command (m for help): p // 查看分区表
Disk /dev/sdb: 20 GiB, 21474836480 bytes, 41943040 sectors
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: 0x178d8de5
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 10487807 10485760 5G 83 Linux
/dev/sdb2 10487808 41943039 31455232 15G 5 Extended // 创建好了一个逻辑分区大小为15G
Command (m for help): w // 保存分区操作
The partition table has been altered.
Syncing disks.
[root@host ~]# lsblk -p
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb1 8:17 0 5G 0 part /sdb1
└─/dev/sdb2 8:18 0 15G 0 part
/dev/sr0 11:0 1 1024M 0 rom逻辑子分区
创建好逻辑分区之后就可以在逻辑分区里面创建无数个子分区，这样就逃离了MBR分区方式的分区限制。
[root@host ~]# fdisk /dev/sdb // 对/dev/sdb进行分区
Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): n // 新建分区
All space for primary partitions is in use.
Adding logical partition 5 // 当创建好逻辑分区之后就会发现分区号会从5开始增加
First sector (10489856-41943039, default 10489856): // 磁盘起始位置，默认即可
Last sector, +sectors or +size{K,M,G,T,P} (10489856-41943039, default 41943039): +1G //设置大小
Created a new partition 5 of type 'Linux' and of size 1 GiB.
Command (m for help): n // 继续创建
All space for primary partitions is in use.
Adding logical partition 6
First sector (12589056-41943039, default 12589056):
Last sector, +sectors or +size{K,M,G,T,P} (12589056-41943039, default 41943039): +1G
Created a new partition 6 of type 'Linux' and of size 1 GiB.
Command (m for help): n // 继续创建
All space for primary partitions is in use.
Adding logical partition 7
First sector (14688256-41943039, default 14688256):
Last sector, +sectors or +size{K,M,G,T,P} (14688256-41943039, default 41943039): +1G
Created a new partition 7 of type 'Linux' and of size 1 GiB.
Command (m for help): w // 保存
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
[root@host ~]# lsblk -p // 查看分区表
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb1 8:17 0 5G 0 part /sdb1
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom这里会发现sdb磁盘一共创建了7个分区。
删除分区
以sdb1为例，sdb1这个分区已经挂载到了/sdb1目录已经在使用了，在删除分区前需要取消挂载。具体操作方法如下
[root@host ~]# lsblk -p // 查看分区状态
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb1 8:17 0 5G 0 part /sdb1 // 发现/dev/sdb1已经挂载到/sdb1目录下
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom
[root@host ~]# umount /sdb1 // 取消挂载
[root@host ~]# lsblk -p
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb1 8:17 0 5G 0 part // 已经取消挂载了
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom
[root@host ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): d // d(delete)删除分区
Partition number (1,2,5-7, default 7): 1 // 删除分区号，这里选择1
Partition 1 has been deleted.
Command (m for help): w // 保存位置
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.
[root@host ~]# lsblk -p // 查看磁盘状态
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk // 发现sdb1已经消失
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom使用分区
格式化分区
创建好分区之后需要格式化之后才可以挂载使用，格式化需要使用mkfs工具，这里不多讲。关于格式化的格式可以使用mkfs.
[root@host ~]# mkfs.
mkfs.cramfs mkfs.ext2 mkfs.ext3 mkfs.ext4 mkfs.minix mkfs.xfs这里使用xfs来格式化创建的分区(逻辑分区只能格式化子分区不能直接格式化逻辑分区)。
[root@host ~]# lsblk -p // 查看分区状态
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom
[root@host ~]# mkfs.xfs /dev/sdb5 // 使用xfs类型格式化sdb5
meta-data=/dev/sdb5 isize=512 agcount=4, agsize=65536 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=262144, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@host ~]# mkfs.xfs /dev/sdb6 // 使用xfs类型格式化sdb6
meta-data=/dev/sdb6 isize=512 agcount=4, agsize=65536 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=262144, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@host ~]# mkfs.xfs /dev/sdb7 // 使用xfs类型格式化sdb7
meta-data=/dev/sdb7 isize=512 agcount=4, agsize=65536 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=1, rmapbt=0
= reflink=1
data = bsize=4096 blocks=262144, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0, ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@host ~]# lsblk -p // 查看分区状态
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part
├─/dev/sdb6 8:22 0 1G 0 part
└─/dev/sdb7 8:23 0 1G 0 part
/dev/sr0 11:0 1 1024M 0 rom挂载分区
当格式化分区之后可以通过mount来进行挂载，挂载好的分区就可以使用了。
[root@host ~]# mkdir -p /disk/sdb{5..7} // 创建挂载目录
[root@host ~]# mount /dev/sdb5 /disk/sdb5 // 挂载sdb5
[root@host ~]# mount /dev/sdb6 /disk/sdb6 // 挂载sdb6
[root@host ~]# mount /dev/sdb7 /disk/sdb7 // 挂载sdb7
[root@host ~]# lsblk -p // 查看分区状态
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
/dev/sda 8:0 0 20G 0 disk
├─/dev/sda1 8:1 0 1G 0 part /boot
└─/dev/sda2 8:2 0 19G 0 part
├─/dev/mapper/rl-root 253:0 0 17G 0 lvm /
└─/dev/mapper/rl-swap 253:1 0 2G 0 lvm [SWAP]
/dev/sdb 8:16 0 20G 0 disk
├─/dev/sdb2 8:18 0 1K 0 part
├─/dev/sdb5 8:21 0 1G 0 part /disk/sdb5
├─/dev/sdb6 8:22 0 1G 0 part /disk/sdb6
└─/dev/sdb7 8:23 0 1G 0 part /disk/sdb7
/dev/sr0 11:0 1 1024M 0 rom