Linux挂载分区及挂在访问的概念

使用fdisk命令对硬盘进行分区
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首先查看 /dev/sde硬盘
[root@localhost ~]# fdisk -l /dev/sde

Disk /dev/sde: 21.5 GB, 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

然后进行编辑

[root@localhost ~]# fdisk /dev/sde
Welcome to fdisk (util-linux 2.23.2).

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
Building a new DOS disklabel with disk identifier 0x799f206b.

Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
g create a new empty GPT partition table
G create an IRIX (SGI) partition table
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)

Command (m for help):

输入参数n 添加一个主分区
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
First sector (2048-41943039, default 2048): --->开始节点默认，直接回车即可
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +1G --->主分区可以分小一点 ，结束节点+1G

然后继续输入n添加，扩展分区输入 e
Command (m for help): n
Partition type:
p primary (1 primary, 0 extended, 3 free)
e extended
Select (default p): e
Partition number (2-4, default 2):
First sector (2099200-41943039, default 2099200):
Using default value 2099200
Last sector, +sectors or +size{K,M,G} (2099200-41943039, default 41943039): ---->扩展分区的结束节点不输入数字，直接回车，即表示将剩余的空间全部给扩展分区
Using default value 41943039
Partition 2 of type Extended and of size 19 GiB is set

输入p查看：此时有一个扩展分区和一个主分区
Command (m for help): p

Disk /dev/sde: 21.5 GB, 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
Disk label type: dos
Disk identifier: 0x799f206b

Device Boot Start End Blocks Id System
/dev/sde1 2048 2099199 1048576 83 Linux
/dev/sde2 2099200 41943039 19921920 5 Extended

再次输入n，添加逻辑分区，分10G
Command (m for help): n
Partition type:
p primary (1 primary, 1 extended, 2 free)
l logical (numbered from 5)
Select (default p): l
Adding logical partition 5
First sector (2101248-41943039, default 2101248):
Using default value 2101248
Value out of range.
Last sector, +sectors or +size{K,M,G} (2101248-41943039, default 41943039): +10G
Partition 5 of type Linux and of size 10 GiB is set

打印查看：
Command (m for help): p

Disk /dev/sde: 21.5 GB, 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
Disk label type: dos
Disk identifier: 0x799f206b

Device Boot Start End Blocks Id System
/dev/sde1 2048 2099199 1048576 83 Linux
/dev/sde2 2099200 41943039 19921920 5 Extended
/dev/sde5 2101248 23072767 10485760 83 Linux

继续添加逻辑分区，将剩余空间全部分给最后一个逻辑分区：

Command (m for help): n
Partition type:
p primary (1 primary, 1 extended, 2 free)
l logical (numbered from 5)
Select (default p): l
Adding logical partition 6
First sector (23074816-41943039, default 23074816):
Using default value 23074816
Last sector, +sectors or +size{K,M,G} (23074816-41943039, default 41943039):
Using default value 41943039
Partition 6 of type Linux and of size 9 GiB is set

Command (m for help): p

Disk /dev/sde: 21.5 GB, 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
Disk label type: dos
Disk identifier: 0x799f206b

Device Boot Start End Blocks Id System
/dev/sde1 2048 2099199 1048576 83 Linux
/dev/sde2 2099200 41943039 19921920 5 Extended
/dev/sde5 2101248 23072767 10485760 83 Linux
/dev/sde6 23074816 41943039 9434112 83 Linux

最后输入w写入
Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

使用lsblk查看硬盘：
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 19G 0 part
├─centos-root 253:0 0 35.6G 0 lvm /
└─centos-swap 253:1 0 6G 0 lvm [SWAP]
sdb 8:16 0 20G 0 disk
└─sdb1 8:17 0 20G 0 part
├─centos-root 253:0 0 35.6G 0 lvm /
└─centos-home 253:2 0 17.4G 0 lvm /home
sdc 8:32 0 20G 0 disk
└─sdc1 8:33 0 20G 0 part
└─centos-root 253:0 0 35.6G 0 lvm /
sdd 8:48 0 20G 0 disk
├─sdd1 8:49 0 10G 0 part
├─sdd2 8:50 0 5G 0 part
└─sdd3 8:51 0 5G 0 part
sde 8:64 0 20G 0 disk
├─sde1 8:65 0 1G 0 part
├─sde2 8:66 0 1K 0 part
├─sde5 8:69 0 10G 0 part
└─sde6 8:70 0 9G 0 part
sr0 11:0 1 4.4G 0 rom

此时sde被分成了5个分区，其中数据可以往sde5、sde6写入
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sda是在安装系统的时候，系统分区的硬盘，其中分了一个sad1 只有1G空间用来存放启动文件的，数据都写入到sda2里，sda2挂在了根目录/

此时假如我在任意区域创建一个目录：mkdir /my_dev 如果这个目录还没有做任何挂在，则数据还是会默认写入到sda中，实质上还是属于在根目录下创建的文件夹

当这个文件夹挂载到了/dev/sde5中：mount /dev/sde5 /my_dev 此时再写数据，就会写入到/dev/sde5中，例如创建一个日志文件：touch logfile.log 此时这个log文件会写入到/dev/sde5中；此时访问/my_dev这个文件夹就是管理/dev/sde5这个分区