Linux disk knowledge, partitioning and file system

The performance of hardware devices in Linux systems

Device files

I/O ports:i/o device Address

All documents:

Open (), read (), write (), close ()

Device Type:

Block devices: block, Access unit "blocks", disk

Character device: Char, Access unit "character", keyboard

Device files: Linked to a device driver to communicate with the corresponding hardware device

Device number:

Main device number: Major numbers, identifying device types

Second device number: Minor numbers, identifying different devices under the same type

Hard Disk interface type

Parallel:

ide:133mb/s

scsi:640mb/s

Serial:

sata:6gbps

sas:6gbps

usb:480mb/s

Rpm:rotations per minute (RPM)

Device files

Device file name for disk device:/dev/dev_file

IDE:/DEV/HD

SCSI, SATA, SAS, USB:/DEV/SD

Different devices: A-Z

/DEV/SDA,/dev/sdb, ...

Different partitions on the same device: 1, 2, ...

/DEV/SDA1,/dev/sda5

Physical structure of hard disk

Hard disk storage Terminology

Head: Head

Track: Tracks

Cylinder: Cylinder surface

SECOTR: Fan area, 512bytes

Using partitioned space

Device identification

Device Partitioning

Creating a file system

Tag File system

Create an entry in the/etc/fstab file

Mount a new file system

Disk partitioning

Why a partition?

Optimizing I/O performance

Implementing disk space Quota limits

Improved repair speed

Isolating systems and programs

Install multiple OS

Hard disk Partitioning

Why a partition?

Optimizing I/O performance

Implementing disk space Quota limits

Improved repair speed

Isolating systems and programs

Install multiple OS

Partition

Two ways to partition: MBR, GPT

Mbr:master boot Record, 1982, using 32-bit representation of sector number, partitions not exceeding 2T

How to partition: Press Cylinder

0 Track 0 Sector: 512bytes

446bytes:boot Loader

64bytes: Partition Table

16bytes: Identify a partition

2bytes:55aa

4 primary partition, 3 primary partition +1 extension (n logical partition)

MBR partition structure

GPT Partition

Gpt:guid patition Table supports 128 partitions, using 64-bit, supported

Holding 8Z (512byte/block) 64Z (4096byte/block)

Using a 128-bit UUID indicates that the disk and partition GPT partition tables are automatically backed up in the header

and two parts of the tail, and a CRC check bit

UEFI (Unified extension Firmware interface) hardware support GPT

GPT partition structure

The EFI section can also be divided into 4 areas: EFI Information area (GPT header), partition table, GPT partition, backup area

Managing partitions

List block devices

Blkid

To create a partition using:

FDISK creates an MBR partition, also supports GPT, and can manage up to 15 partitions for a hard disk

Gdisk creating a GPT partition

GNU parted advanced partitioning operations (create, copy, resize, etc.)

partprobe-re-setting the kernel partition table version in memory

Fdisk/dev/sdb

Gfisk/dev/sdb

# fdisk-l [-u] [device ...]

Sub-command:

P Partition List

t change the partition type

n Create a new partition

D Delete Partition

W Save and exit

Q Do not save and exit

Partitioning tools Fdisk and Gdisk

Synchronizing partitioned Tables

To see if the kernel has identified a new partition:

# cat/proc/partations

Notifies the kernel to re-read the hard disk partition table

New Partition with

Partx-a-N m:n/dev/device

Kpartx-a/dev/device-f: Force

Delete partition with

Partx-d-N m:n/dev/device

Centos6:–nr n-m

CentOS 5, 7: Using Partprobe

Partprobe [/dev/device]

parted command

Parted operations are in real time, use caution

Usage: parted [options] ... [Device [command [parameters] ...] ...]

Parted/dev/sdb Mklabel Gpt|msdos

PARTED/DEV/SDB Print

Parted/dev/sdb Mkpart Primary 1 200 (default m)

PARTED/DEV/SDB RM 1

Parted-l

File system

A file system is a party that the operating system uses to explicitly store files on a device or partition

The method of organizing files on the storage device. Operating system

The software structure for managing and storing file information is called a file management system,

Abbreviation file system.

From a system point of view, a file system is a group of space for a file storage device

and distribution, responsible for file storage and protection and retrieval of documents deposited

System. Specifically, it is responsible for creating files for users, depositing, reading, repairing

Change, dump files, control file access, security control, logs, compression,

Encryption, and so on.

File system type

Linux file systems: ext2, Ext3, Ext4, XFS (SGI), Btrfs (

Oracle), ReiserFS, JFS (AIX), swap

Swap: Swap partition

Disc: iso9660

Windows:fat32, NTFS

Unix:ffs (FAST), UFS (Unix), JFS2

Network File system: NFS, CIFS

Clustered file system: GFS2, OCFS2 (Oracle)

Distributed File systems: Ceph, Moosefs, MogileFS, Glusterfs,lustre

RAW: Unprocessed or unformatted file system

File System classification

Depending on whether it supports the "journal" feature:

journaled file system: ext3, Ext4, XFS, ...

Non-journaled file system: ext2, VFAT

Part of the file system:

Modules in the kernel: Ext4, XFS, VFAT

User space management tools: MKFS.EXT4, Mkfs.xfs,mkfs.vfat

Virtual file system for Linux: VFS

Pre-check supported file systems: Cat/proc/filesystems

Creating a file system

MKFS command:

(1) # MKFS. Fs_type/dev/device

Ext4

Xfs

Btrfs

Vfat

(2) # mkfs-t Fs_type/dev/device

-L ' LABEL ': Set volume label

Create ext File System

Mke2fs:ext Series file system dedicated management tools

-T {EXT2|EXT3|EXT4}

-B {1024|2048|4096}

&nbs

Linux disk knowledge, partitioning and file system