brief introduction
When you learn Linux, you need to learn partitions in Linux. Learning Linux partitioning, there are many conceptual things to learn, such as partition type, file system type, etc. Wait a minute. For me, I don't like this kind of conceptual thing very much. It's not at all friendly for me to come up with a large paragraph of text. So I organized a note to record how to partition disks in Linux, create file systems and mount them. First, it can be used practically, then slowly understand the content.
Environmental Introduction
Operating System: CentOS 6.6
Introduction to Commands
Partition command
fdisk partition
Fdisk can be used to view hard disk partitions, or fdisk can be used to partition.
Options:
- b SECTOR_SIZE: Specify the size of each partition - l: List partitions for the specified hard disk - s PARTITION: Outputs the size of the specified partition in blocks - u: When listing hard disk partitions, use blocks to list partition sizes instead of cylinders - v: Display version information
Suboptions:
p:print, showing existing partitions n:new, create d:delete, delete w:write, write to disk and exit q:quit, give up updating and quit m: Get help l: List partitioned id t: Adjust partition id
Parx Recognition Partition
* Options:*
- a: Notify the kernel to re-read the hard disk partition table - d: Delete partition table information for partitioned hard disks - l: List partitions TypeYTPE: Specify partition type - nr M-N: Specified partition range
Create File System Command
mkfs Create File System
Options:
- t TYPE: Specifies the file system type of the piercer - v: Display version information - c: Before creating a file system, check the partition for bad blocks
mkswap creates swap partitions
Options:
- c: Before creating a swap partition, check that there are bad blocks in the partition - f: Enforcement
Mount command
Mount mount partition
mount [-fnrsvw] [-t vfstype] [-o options] device dir
Options:
-t vsftype:Specify the file system type on the device to be mounted
-r : readonly，Read-only mounting
-w: read and write，Read-write mount
-n: No updates/etc/fstab
-a: Automatic mounting of all devices that support automatic mounting (defined in/etc/fstab In the file, and the mount option has the "automatic mount" function.
-L 'LABEL': Specify mounting devices with volume labels
-U 'UUID': withUUIDSpecify the device to mount
-B，--bind: Bind directories to another directory
-o options:Options for mounting file systems
async: Asynchronous mode
sync: Synchronization mode
atime/noatime:Contains directories and files
diratime/nodiratime:Directory access timestamp
auto/noauto:Whether Automount is Supported
exec/noexec:Supports running applications on file systems as processes
dev/nodev:Do you support using devices on this file system?
suid/nosuid；
remount: remount
ro: Read-only mounting
rw: Read-write mount
user/nouser:Whether Ordinary Users are allowed to mount this device
acl: Enable this file system acl function
defaults: rw,suid,dev,exec,auto,nouser,and asyncumount uninstall partition
umount [-dflnrv] {dir|device}...
Options:
- a: Remove all file systems recorded in / etc/mtab; - h: Display help; - n: Do not store information in / etc/mtab file when uninstalling. - r: If you can't uninstall it successfully, try to re-mount the file system in a read-only way. - T < File System Type >: Unmount only the file system specified in the option; - v: Display detailed information during execution; - V: Display version information.
swapon enables swap partitions
swapon [-f] [-p priority] [-v] specialfile...
Options:
- a: Activate all switching partitions - p PRIORITY: Specify Priority
swapoff disables swap partitions
swapoff [-v] specialfile...
Options:
- a: Disable all swap partitions
Introduction of steps
Ordinary partitions are created and mounted
- View hard disks and partitions
[root@sg-pc /]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sr0 11:0 1 4.3G 0 rom
sda 8:0 0 20G 0 disk
├─sda1 8:1 0 500M 0 part /boot
└─sda2 8:2 0 19.5G 0 part
├─vg_sgpc-lv_root (dm-0) 253:0 0 17.6G 0 lvm /
└─vg_sgpc-lv_swap (dm-1) 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 20G 0 disk
[root@sg-pc /]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x179a39d6
Device Boot Start End Blocks Id System
Command (m for help): - fdisk is used to partition the / dev/sdb hard disk into three main partitions, each of which is 5G in size, and an extended partition, 4G in size.
[root@sg-pc /]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-2610, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +5G
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (655-2610, default 655):
Using default value 655
Last cylinder, +cylinders or +size{K,M,G} (655-2610, default 2610): +5G
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
First cylinder (1309-2610, default 1309):
Using default value 1309
Last cylinder, +cylinders or +size{K,M,G} (1309-2610, default 2610): +5G
Command (m for help): n
Command action
e extended
p primary partition (1-4)
e
Selected partition 4
First cylinder (1963-2610, default 1963):
Using default value 1963
Last cylinder, +cylinders or +size{K,M,G} (1963-2610, default 2610): +2610
Value out of range.
Last cylinder, +cylinders or +size{K,M,G} (1963-2610, default 2610):
Using default value 2610
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x179a39d6
Device Boot Start End Blocks Id System
/dev/sdb1 1 654 5253223+ 83 Linux
/dev/sdb2 655 1308 5253255 83 Linux
/dev/sdb3 1309 1962 5253255 83 Linux
/dev/sdb4 1963 2610 5205060 5 Extended
Command (m for help): n
First cylinder (1963-2610, default 1963):
Using default value 1963
Last cylinder, +cylinders or +size{K,M,G} (1963-2610, default 2610): +2G
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x179a39d6
Device Boot Start End Blocks Id System
/dev/sdb1 1 654 5253223+ 83 Linux
/dev/sdb2 655 1308 5253255 83 Linux
/dev/sdb3 1309 1962 5253255 83 Linux
/dev/sdb4 1963 2610 5205060 5 Extended
/dev/sdb5 1963 2224 2104483+ 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.- Load the newly partitioned partition into the hard disk partition table and view the partition status
[root@sg-pc /]# partx -a /dev/sdb
BLKPG: Device or resource busy
error adding partition 1
BLKPG: Device or resource busy
error adding partition 2
BLKPG: Device or resource busy
error adding partition 3
BLKPG: Device or resource busy
error adding partition 4
BLKPG: Device or resource busy
error adding partition 5
[root@sg-pc /]# cat /proc/partitions
major minor #blocks name
8 0 20971520 sda
8 1 512000 sda1
8 2 20458496 sda2
8 16 20971520 sdb
8 17 5253223 sdb1
8 18 5253255 sdb2
8 19 5253255 sdb3
8 20 1 sdb4
8 21 2104483 sdb5
253 0 18391040 dm-0
253 1 2064384 dm-1- Create a filesystem for the partition, and select the / dev/sdb1 partition as an example
[root@sg-pc /]# mkfs -t ext4 -L 'backup' /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=backup
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
328656 inodes, 1313305 blocks
65665 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1346371584
41 block groups
32768 blocks per group, 32768 fragments per group
8016 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 25 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.- Through the blkid command, you can view the information of the hard disk device
[root@sg-pc /]# blkid
/dev/sda1: UUID="5e605252-9e26-4ca0-b353-e3e6028bc6ca" TYPE="ext4"
/dev/sda2: UUID="drR3Sx-Ht8g-nGFi-2vR3-CD3z-qSjY-PUXiye" TYPE="LVM2_member"
/dev/mapper/vg_sgpc-lv_root: UUID="9ccc9289-ada6-48b8-82f1-42d2f7edba06" TYPE="ext4"
/dev/mapper/vg_sgpc-lv_swap: UUID="9c4c6c97-b20d-4548-a249-8d98f6b400f1" TYPE="swap"
/dev/sdb1: LABEL="backup" UUID="4a7b5acb-fc24-446d-b9e0-a14afbe171d9" TYPE="ext4"
/dev/sdb2: LABEL="myswap" UUID="79f07b7d-c504-43c2-9e0f-87bee77d59b9" TYPE="swap" - Mount the partition that has created the file system in the specified directory
[root@sg-pc /]# mkdir /backup
[root@sg-pc /]# mount /dev/sdb1 /backup/- Check partition mounting
You can see that / dev/sdb1 has been mounted in the / backup directory.
Creation and mounting of switching partitions
The creation and mounting steps of the swap partition are the same as those of the ordinary partition. It also divides the partition first, then creates the file system on the partition, and then activates the swap partition. Because the swap partition is a little different from the normal partition, the partition ID of the partition needs to be adjusted first.
- To use the / dev/sdb2 partition as a swap partition, you first need to modify the partition ID of the / dev/sdb2 partition
[root@sg-pc /]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x179a39d6
Device Boot Start End Blocks Id System
/dev/sdb1 1 654 5253223+ 83 Linux
/dev/sdb2 655 1308 5253255 83 Linux
/dev/sdb3 1309 1962 5253255 83 Linux
/dev/sdb4 1963 2610 5205060 5 Extended
/dev/sdb5 1963 2224 2104483+ 83 Linux
Command (m for help): l
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 39 Plan 9 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 3c PartitionMagic 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 40 Venix 80286 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 41 PPC PReP Boot 85 Linux extended c7 Syrinx
5 Extended 42 SFS 86 NTFS volume set da Non-FS data
6 FAT16 4d QNX4.x 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS 4e QNX4.x 2nd part 88 Linux plaintext de Dell Utility
8 AIX 4f QNX4.x 3rd part 8e Linux LVM df BootIt
9 AIX bootable 50 OnTrack DM 93 Amoeba e1 DOS access
a OS/2 Boot Manag 51 OnTrack DM6 Aux 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 52 CP/M 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 53 OnTrack DM6 Aux a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 54 OnTrackDM6 a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 55 EZ-Drive a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 56 Golden Bow a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 5c Priam Edisk a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 61 SpeedStor a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 63 GNU HURD or Sys ab Darwin boot f2 DOS secondary
16 Hidden FAT16 64 Novell Netware af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 65 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 70 DiskSecure Mult b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 75 PC/IX bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 80 Old Minix be Solaris boot ff BBT
1e Hidden W95 FAT1
Command (m for help): t
Partition number (1-5): 2
Hex code (type L to list codes): 82
Changed system type of partition 2 to 82 (Linux swap / Solaris)
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.- File system for creating swap partitions
[root@sg-pc /]# mkswap -L 'myswap' /dev/sdb2
Setting up swapspace version 1, size = 5253248 KiB
LABEL=myswap, UUID=fee42b41-d38f-498e-a27f-70a962734a26- Activate switching partitions
[root@sg-pc /]# free -m
total used free shared buffers cached
Mem: 996 642 354 1 112 304
-/+ buffers/cache: 224 771
Swap: 2015 0 2015
[root@sg-pc /]# swapon -a /dev/sdb2
[root@sg-pc /]# free -m
total used free shared buffers cached
Mem: 996 645 350 1 112 304
-/+ buffers/cache: 228 767
Swap: 7146 0 7146Auto-mounting of partition boot-up
The partitions of the hard disk mentioned above are temporarily mounted in the system. When the system restarts, the partitions we mount will not be automatically mounted at present, and we need to perform the steps of mounting, which is very inconvenient. If we need the hard disk partition to be mounted automatically when the system restarts, we need to write the partition configuration to the file / etc/fstab. 
/ Each line in the etc/fstab file represents a hard disk partition that needs to be automatically mounted at startup.
Each row of record friends consists of six fields, in the order of:
* Equipment to be mounted
* mount point
* File system type
* Mount options
Generally defaults
* Dump frequency
Refers to the frequency of backup, 0 means no backup, 1 means backup every day, 2 means backup every other day.
* Self-checking order
0 means not self-checking
1 means self-checking first, the larger the value, the lower the order of self-checking.
Example
Let's take the. / dev/sdb1 partition as an example and set it to mount the / dev/sdb1 partition to the corresponding mount point every time the machine restarts. 
Add a line as shown in the / etc/fstab file to indicate that every time the machine restarts, the / dev/sdb1 partition will be mounted on the / backup mount point, and the file system type of the partition is ext4, the mount option is defautls, no backup, no self-checking.
summary
Generally speaking, hard disk partitioning and mounting under Linux are mainly three steps:
1. Partition
2. Creating a File System
3. Mount partition