Linux system creates primary partition, logical partition, sets parameters of ext series partition and methods of partition detection

Time:2020-1-13

Linux names the device files of different disk devices as follows:

        IDE: /dev/hd[a-z]
The name of the IDE partition is / dev / hda1 / dev / hda2 ..
        SCSI, SATA, SAS, USB: /dev/sd[a-z]
The command to the partition is / dev / sda1 / dev / sda2 .
There can be up to four primary partitions. If there are more than 4 partitions, you can use the method of three primary partitions plus one extended partition, and then divide multiple logical partitions on the extended partition.
Common file formats include ext2, ext3, ext4, VFAT (compatible with FAT32 of windows), XFS, Btrfs, JFS, etc.

To view the partition of Linux, you can use FDIS (partition management command)

Fdisk / dev / SDA (non IDE hard disk)
M: get help
P: display partition information
Q: exit without saving
N: new partition
D: delete partition
Q: save exit
L: displays the ID of the partition type
T: change the ID of the partition type

[[email protected] ~]# fdisk /dev/sda

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.
Command (m for help): p
Disk /dev/sda: 16.1 GB, 16106127360 bytes, 31457280 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: 0x000a72d4
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048    20971519     9972736   8e  Linux LVM

Explain:

1. Disk / dev / SDA: the size of 16.1gb hard disk is 16GB, 16106127360 bytes, 31457280 sectors.
2. Information description of the second half
Device is the partition name
Whether boot is a boot partition
Sector from start
End end sector \ \ / dev / sda2 end sector is 20971519, and the total hard disk is 31457280, indicating that there is still hard disk space not used to create partitions.
Blocks displays the space of the partition in 1KB;
LD is the ID number of the partition type
System is partition type

Create a partition: (the starting sector and the ending sector of / dev / sda2 specified in the figure below can be docked)

 Create logical partition

Command (m for help): n

Partition type:

   p   primary (3 primary, 0 extended, 1 free)

   e   extended

Select (default e): e   \\Specify new extended partition

Selected partition 4

First sector (23068672-31457279, default 23068672): 

Using default value 23068672

Last sector, +sectors or +size{K,M,G} (23068672-31457279, default 31457279): +1G  \\Specify the size of the extended partition

Partition 4 of type Extended and of size 1 GiB is set

Command (m for help): n 

All primary partitions are in use

Adding logical partition 5  \\The ID number 1-4 has been used up. The system directly uses the range of logical partition ID 5-15

First sector (23070720-25165823, default 23070720): 

Using default value 23070720

Last sector, +sectors or +size{K,M,G} (23070720-25165823, default 25165823): 24000000 \ \ end sector here25165823-23070720=2095103*512/1024/1024=1022.99MB, or 1GB, is the same size as the specified expansion partition

Partition 5 of type Linux and of size 453.8 MiB is set\\The size of the new logical partition is 453.8mb

Command (m for help): n

All primary partitions are in use

Adding logical partition 6

First sector (24002049-25165823, default 24002560): 

Using default value 24002560

Last sector, +sectors or +size{K,M,G} (24002560-25165823, default 25165823):  \\The end sector ID here is the same as above

Using default value 25165823

Partition 6 of type Linux and of size 568 MiB is set

Command (m for help): p

Disk /dev/sda: 16.1 GB, 16106127360 bytes, 31457280 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: 0x000a72d4

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *        2048     1026047      512000   83  Linux

/dev/sda2         1026048    20971519     9972736   8e  Linux LVM

/dev/sda3        20971520    23068671     1048576   83  Linux

/dev/sda4        23068672    25165823     1048576    5  Extended

/dev/sda5        23070720    24000000      464640+  83  Linux

/Dev / sda6 24002560 25165823 581632 83 Linux \ \ new logical partition

Command (m for help): w \\Save exit

Check whether Linux has recognized the new partition. Check the / RROC / partitions file

[[email protected] ~]# cat /proc/partitions 

major minor  #blocks  name

   8        0   15728640 sda

   8        1     512000 sda1

   8        2    9972736 sda2  \\The newly created / dev / sda3-6 has not been recognized yet

  11        0    4228096 sr0

 253        0    8880128 dm-0

 253        1    1048576 dm-1

Force kernel to update partition

[[email protected] ~]# partx -u /dev/sda 

[[email protected] ~]# cat /proc/partitions 

major minor  #blocks  name

   8        0   15728640 sda

   8        1     512000 sda1

   8        2    9972736 sda2

   8        3    1048576 sda3

   8        4          1 sda4

   8        5     464640 sda5

   8        6     581632 sda6 \\New partition identified

  11        0    4228096 sr0

 253        0    8880128 dm-0

 253        1    1048576 dm-1

[[email protected] ~]# 

Format new partition mkfs command

    Format sda6 and sda5 as ext4

[[email protected] ~]# mkfs.ext4 -L test /dev/sda6

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=test

OS type: Linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

36400 inodes, 145408 blocks

7270 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=148897792

5 block groups

32768 blocks per group, 32768 fragments per group

7280 inodes per group

Superblock backups stored on blocks: 

32768, 98304

Allocating group tables: done                            

Writing inode tables: done                            

Creating journal (4096 blocks): done

Writing superblocks and filesystem accounting information: done


You can also use the special format tool mke2fs of ext series

[[email protected] ~]# mke2fs -t ext3 -m 5 -L TEST_sda5 -b 4096 /dev/sda5 

mke2fs 1.42.9 (28-Dec-2013)

Filesystem label=TEST_sda5 \\The identifier is test? Sda5

OS type: Linux

Block size=4096 (log=2) \\Block is 4096

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

116224 inodes, 116160 blocks

5808 blocks (5.00%) reserved for the super user \\5% space for administrators

First data block=0

Maximum filesystem blocks=121634816

4 block groups

32768 blocks per group, 32768 fragments per group

29056 inodes per group

Superblock backups stored on blocks: 

32768, 98304

Allocating group tables: done                            

Writing inode tables: done                            

Creating journal (4096 blocks): done

Writing superblocks and filesystem accounting information: done

View properties of all partitions using blkid

[[email protected] ~]# blkid 

/dev/sda1: UUID=”050a347a-4a99-4e80-a6b4-a4ed0a47eaa1″ TYPE=”xfs” 

/dev/sda2: UUID=”dv2Krn-BlSL-4NBt-yduR-BXax-tChJ-V2YpbM” TYPE=”LVM2_member” 

/dev/sda5: LABEL=”TEST_sda5″ UUID=”b5b2b12b-236d-4578-845b-a5632ca5eafa” SEC_TYPE=”ext2″ TYPE=”ext3″  

/dev/sda6: LABEL=”test” UUID=”a0a549a2-0aec-4ff6-bce8-f2dfdfa1539e” TYPE=”ext4″  

/dev/sr0: UUID=”2015-12-09-23-14-10-00″ LABEL=”CentOS 7 x86_64″ TYPE=”iso9660″ PTTYPE=”dos” 

/dev/mapper/centos-root: UUID=”0adba78a-e1e3-4900-87c2-069105c6a1fc” TYPE=”xfs” 

/dev/mapper/centos-swap: UUID=”2228d7dd-b7ed-44fb-9f68-668fc942a542″ TYPE=”swap” 

Use fsck command to detect partition

[[email protected] ~]# fsck.ext3 -frc /dev/sda5   \\F is mandatory detection C is to prompt the test progress r for interactive detection

e2fsck 1.42.9 (28-Dec-2013)

Checking for bad blocks (read-only test): done                                                 

TEST_sda5: Updating bad block inode.

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

TEST_sda5: ***** FILE SYSTEM WAS MODIFIED *****

TEST_sda5: 11/116224 files (0.0% non-contiguous), 7837/116160 blocks

[[email protected] ~]#