Check how many partitions there are in linux

How to check how many partitions there are in Linux: 1. Open the Linux terminal window; 2. Enter the "Fdisk-L" command and press Enter; 3. View the partition list in the terminal window and view the disk The partition information is sufficient.

#The operating environment of this tutorial: linux5.9.8 system, Dell G3 computer.

How many partitions does Linux have?

How to check the partition situation in LINUX:

1. First, open the terminal and enter Fdisk -L and press Enter.

2. This is the partition list.

#3. Find two 40G partition words in the picture. These two are the partitions of our hard disk.

4. The information in the red box is that the disk partition information size is 40G, so sDA and SDB have different meanings.

#5. All the equipment in the red box below are listed to complete the rendering.

Related introduction:

df command

df output disk file system usage:

[root@centos ~]# df
文件系统          1K-块    已用    可用 已用% 挂载点
/dev/sda3      11208704 7214792 3993912   65% /
devtmpfs         496920       0  496920    0% /dev
tmpfs            507752       0  507752    0% /dev/shm
tmpfs            507752    6852  500900    2% /run
tmpfs            507752       0  507752    0% /sys/fs/cgroup
/dev/sda1        201380  103660   97720   52% /boot
tmpfs            101552       0  101552    0% /run/user/0

Mainly focus on used percentage and mount points. The one with the words tmpfs is a temporary file system. The data is not saved after the system is powered off. /dev/sda is our disk.

There are several common parameters, -h is displayed in appropriate units, and the default "used" column is KB. -m displays the disk usage in MB. -i displays inode usage. When the disk is formatted, inode and block are generated. I want to draw a grid on a piece of paper. The grid where the content can be stored is block, and inode is the directory index pointing to the block. Linux may encounter an situation where the inode is used up and there is still a block left, but at this time the system cannot write files to the disk.

Computer storage media units mainly include Byte, KB, MB, GB, and TB. The above are arranged in ascending order, and the conversion base is 1024. There is also a smaller unit called bit, which represents 0 or 1, which can be said to convey an amount of information. 8bit=1Byte, this conversion base is not 1024. We commonly use Mbps (b is bit, ps is per second) in terms of network transmission speed. We can get inspiration from this unit:

can be understood as the computer transmitting a string of information represented by 01 through the network cable.

The 100M broadband I bought, the maximum download and write speed to the disk is 100Mbit/s=1.25 MB/s

In addition, when installing Linux, the disk is also divided into swap space, which cannot be viewed with the df command. Check the swap space and use free.

du command

du -sh file can check the disk usage of a file or directory. -s displays the total usage. If -s is not added when viewing the directory, the status of each file in the directory will be displayed. -h displays size in appropriate units.

The file size can also be seen in ls -l. But unlike the du command, ls displays the actual file size, while du displays the occupied disk size. In fact, it is quite easy to understand. As mentioned earlier, disk formatting is like drawing a grid on a white paper, so each block will have a certain size to store content. One block cannot contain the contents of multiple files, otherwise it will cause confusion. In other words, even if the file occupies half the block size, this block is no longer used by other files. du measures the file size from the block size, while ls measures it from the amount of bit information stored in the file. Of course du can also view the file content size, you need to use the parameter -sb.

Disk Partition

fdisk -l Check the status of the disk currently mounted on the system. fdisk is also a partitioning tool, and fdisk /dev/sdb is an sdb disk partition. When a new disk is put into use, it is generally partitioned and then formatted, or it can be formatted directly.

Enter the fdisk format partition command into the terminal, enter m to get help, and detailed guidance will be listed. The commonly used ones are: n to create a new partition, w to save the settings, and d to delete the partition. We are experimenting with adding disks to the virtual machine. You may need to restart the virtual machine to recognize the newly created disk. Most real servers support hot-swappable disks.

Use fdisk partition to set up to 4 primary partitions (primary). If there is a need for more partitions, set up 3 primary partitions (primary) and 1 extended partition (extended). Multiple logical partitions can be set up in the extended partition. In short, primary extended

One feature: the logical partition number starts from 5, and the partition numbers are consecutive. The partition numbers of the primary partition may not be consecutive.

After setting the disk partition, be sure to save and exit, otherwise the partition will be lost.

Related recommendations: "Linux Video Tutorial"

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