3 partitioning tools under CentOS Linux
Introduction
With the rapid development of science and technology, more and more companies have higher and higher requirements for the stability of servers. More and more companies are beginning to use the Linux system to deploy their services in order to achieve efficient stability. Of course, any operating system All need a basic foundation, that is, hard disk and hard disk partitioning. Today I will recommend several partitioning tools under CentOS Linux and how to check the partition environment. I will also bring you some basic knowledge of hard disks.
- The interface type of the hard disk
Partitioning is definitely to partition the hard disk, so let’s talk about the interface type of the hard disk first. Now the hard disk is divided into two categories, parallel interface and serial interface. Nowadays, serial interfaces are commonly used on servers and PCs. .
Parallel interfaces are divided into IDE and SCSI interfaces. The disadvantage of parallel interfaces is that electrical signals will interfere during transmission.
Interface rate:
IDE：133MB/s
SCIS:640MB/s
Serial interface, divided into STAT, SAS, USB, three kinds of interfaces, our server and PC also use SATA interface
Serial port:
SATA：6Gbps
SAS：6Gbps
USB：480MB/s
The current disk partition mode is divided into two types, MBR and GPT.
MBR mode
MBR: Master Boot Record, 1982, uses 32 bits to indicate the number of sectors, and the partition does not exceed 2T
The number of partitions that can be partitioned in MBR mode is: 4 primary partitions; 3 primary partitions + 1 expansion (N logical partitions)
Of course, when the hard disk is partitioned, a part of the space is needed to store the partition information. This part of the space is at track 0 and sector 0: 512bytes.
Start 446bytes to store the boot loader
The middle 64bytes stores the partition table, and every 16bytes: identifies a partition
The last 2bytes: store 55AA to indicate the hard disk mode type
GPT mode
GPT: GUID (Globals Unique Identifiers) partition table supports 128 partitions, uses 64 bits, supports 8Z (512Byte/block) and 64Z (4096Byte/block)
Use 128-bit UUID (Universally Unique Identifier) to indicate that the disk and partition GPT partition table is automatically backed up at the beginning and the end, and there is a CRC check bit
UEFI (Unified Extended Firmware Interface) hardware supports GPT to enable the operating system to boot
- Let us see the capabilities of 3 partitioning tools under Linux.
Always strengthen fdisk.
fdisk is a very old partitioning tool in Linux. Although the tool is old, its simplicity and convenience are the advantages of fdisk. Of course, gdisk also inherits this advantage. Their functions are very similar, but the fdisk tool is mainly used for MBR mode. The hard disk is partitioned. The gdisk tool is used to partition the hard disk in GPT mode. Here is a fdisk tool. fdisk cannot partition disks above 2T because MBR mode does not support partition formats above 2T.
fdisk, gdisk tools
fdisk /dev/sdb
fdisk -l [-u] [device...] View hard disk and partition information
Commonly used subcommands:
m help list
p partition list
l View partition type
t change the partition type
n Create a new partition
d Delete partition
w save and exit
After fdisk is partitioned, the operation is just that the hard disk is not partitioned in the memory, if you really need to partition w to save
q Exit without saving
Of course, if you regret it, typing q will not save the previous operation
After the options are introduced, let me give you an experiment. Let everyone know how to use this tool.
[ root@TianRandai ~]#fdisk /dev/sdb #Correct/dev/sdb to operate
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): n #Create a partition
Partition type:
p primary(0 primary,0 extended,4 free)
e extended
Select(default p): p #Partition type is primary partition,p is the primary partition,e is the extended partition
Partition number(1-4,default1):1 #Specify the partition number
First sector(2048-41943039,default2048):
Using default value 2048
Last sector,+sectors or +size{K,M,G}(2048-41943039,default41943039):+2G
Partition 1of type Linux and of size 2 GiB is setCommand(m for help): t #Specify the partition mark type
Selected partition 1
Hex code(type L to list all codes):82
Changed type of partition 'Linux' to 'Linux swap / Solaris'Command(m for help): w #Save operation
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
Powerful partition tool parted
parted
The partitioning of the parted tool is instant operation, so you must be careful when partitioning, because one may accidentally partition the reused hard disk, so you must be cautious when using it.
Usage: parted [option]... [equipment [command [parameter]...]...]
parted /dev/sdb mklabel gpt|msdos specifies the mode for the disk
parted /dev/sdb print shows disk information
parted /dev/sdb mkpart primary/extended/logical 0 200 (default M) partition type and size
parted /dev/sdb rm 1 delete partition
parted -l displays information about all disks
After the options are introduced, let me give you an experiment. Let everyone know how to use this tool.
[ root@TianRandai ~]#parted /dev/sdb mklabel gpt #Specify the disk mode as GPT
Warning: The existing disk label on /dev/sdb will be destroyed and all data on this disk
will be lost. Do you want to continue?
Yes/No? yes
Information: You may need to update /etc/fstab.[root@TianRandai ~]#parted /dev/sdb mkpart primary 0 2G #Create a partition, the partition type is primary partition, the size is 2G
Warning: The resulting partition is not properly aligned for best performance.
Ignore/Cancel? i
Information: You may need to update /etc/fstab.[root@TianRandai ~]#parted /dev/sdb print #View disk information
Model: VMware, VMware Virtual S(scsi)
Disk /dev/sdb:21.5GB
Sector size(logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
117.4 kB 2000MB 2000MB primary
[ root@TianRandai ~]#parted /dev/sdb rm 1 #Delete partition 1
Information: You may need to update /etc/fstab.[root@TianRandai ~]#parted /dev/sdb print #View disk information again
Model: VMware, VMware Virtual S(scsi)
Disk /dev/sdb:21.5GB
Sector size(logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
After the introduction of partitions, we will introduce formatting.
The formatted command can be used
mkfs. File system type Partition
mkfs.ext4 /dev/sdb1
After formatting, you can use mount
[ root@TianRandai ~]#mkfs #Various types of file systems
mkfs mkfs.cramfs mkfs.ext3 mkfs.fat mkfs.msdos mkfs.xfs
mkfs.btrfs mkfs.ext2 mkfs.ext4 mkfs.minix mkfs.vfat
[ root@TianRandai ~]#mkfs.ext4 /dev/sdb1 #will/dev/sdb1 is formatted as ext4
[ root@TianRandai ~]#mkdir /mnt/disk1 #in/mnt/Create a disk1 directory
[ root@TianRandai ~]#mount /dev/sdb1 /mnt/disk1 #Mount the formatted partition to/mnt/disk1 flower girl
[ root@TianRandai ~]#df -h #View mounting and usage
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 10G 4.5G 5.5G 45% /
devtmpfs 898M 0 898M 0%/dev
tmpfs 912M 88K 912M 1%/dev/shm
tmpfs 912M 9.0M 903M 1%/run
tmpfs 912M 0 912M 0%/sys/fs/cgroup
/dev/sda1 1014M 169M 846M 17%/boot
tmpfs 183M 20K 183M 1%/run/user/0/dev/sdb1 1.9G 5.7M 1.7G 1%/mnt/disk1
mkswap format swap type partition
After formatting, swapon is required to enable the formatted partition
To automatically mount at boot, you need to write these configurations to /etc/fstab
The specific mounting method will be explained in detail later.
[ root@TianRandai ~]#free -h #First look at the size of swap
total used free shared buff/cache available
Mem:1.8G 483M 429M 10M 911M 1.1G
Swap:2.0G 0B 2.0G
[ root@TianRandai ~]#mkswap /dev/sdb1 #format/dev/sdb1 partition
mkswap:/dev/sdb1: warning: wiping old ext4 signature.
Setting up swapspace version 1, size =1953104 KiB
no label, UUID=5d9a150e-c247-4c7f-a4be-273a72bd3b5a
[ root@TianRandai ~]#swapon /dev/sdb1 #Enable swap partition
[ root@TianRandai ~]#free -h #Check the swap size again
total used free shared buff/cache available
Mem:1.8G 484M 427M 10M 911M 1.1G
Swap:3.9G 0B 3.9G
If there is the next issue, it will bring you mount mounting, soft Raid technology, and logical volume configuration methods.
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