Linux Disk Management

Linux Disk Management

I/O port:i/o device Address

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

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

Device files: Associate to a device driver to enable communication with the corresponding hardware device

Device number: Primary device number secondary device number

Device files have only source data (attributes), no data, are special types of files, directories are also

/dev/dev_file's here.

The interface type of the hard disk:

Parallel (slower than serial):

IDE 133mb/s (interface rate)

SCSI 640mb/s

Serial:

STAT 6Gbps

SAS 6gbs+

USB 480mb/s

Speed: rpm

Device file command mode for disk devices:

IDE:/DEV/HD

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

CentOS 6 starts with SD

Different devices: A-Z logo/dev/sda/dev/sdb ....

Different partitions for the same device: 1, 2, 3 .... /DEV/SDA1,/dev/sda2 ... .

Mechanical hard disk working mechanism:

Track: Tracks

Cylinder: Cylinder surface

Sector: Sector (512 bytes -4k)

How to Partition:

Partitioning by cylinders

0 cylindrical faces are reserved (512 bytes).

MBR (master boot record main boot record): 46bytes: Storage partition table (each 16 bytes identifies a zone with one pointing to the extended partition (n logical partitions)), 446bytes:boot loader, 2BYTES:55AA

4 Primary partitions: 3 primary partitions + one extension (n logical partitions)

Greater than 2T, to use gpt,http://www.iruanmi.com/what-is-gpt-and-what-is-uefi/

Partition management tools: Fdisk, parted, Sfdisk

FDISK: Only 15 partitions can be managed for a single drive

Fdisk-l (with * number is the boot partition)

Fdisk device:

Sub-command:

P: Show existing partitions

N: Create a new partition

D: Delete

W: Write Update, save exit

Q: Give up

M: Get Help

L: List the partition ID

T: Adjust partition ID (Linux 83, 82)

To see if the kernel has identified a new partition:

Cat/proc/partations should appear on your new partition, otherwise it will not be written

Notifies the kernel to re-read the partition table

Partx-a/dev/device

Partx-n m:n indicate from which to which number

cat/proc/partations

You can also kpartx-a/dev/device (CentOS 5 without this tool, using Partprobe/dev/device)

Linux File System Management

Linux file systems: ext2, Ext3, Ext4, XFS, Btrfs, ReiserFS, JFS, swap

Swap: Swap partition

Windows:fat43,ntfs

Unix:ffs, UFS, JFS2

Network File system: NFS, CIFS

Cluster file system: GFS2, OCFS2

Distributed File systems: Ceph, Moosefs, Mgilefs, GlusterFS, Lustre

Depending on whether it supports the "journal" feature:

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

Non-log file system: Ext2, VFAT

Part of the file system:

Modules in the kernel: EXT4, XFS

User space management tools: MKFS.EXT4, MKFS.XFS, Mkfs.vfat

Virtual file system for Linux: NFS

To create a file system:

To view supported file systems: Cat/proc/filesystems

MKFS command:

(1) # MKFS. Fs_type/dev/device

Xfs

Btrfs

Vfat

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

-L "lable": Set the volume label

Mke2fs:ext Series file system dedicated management tools

-t {ext2| EXT3|EXT4}

-B {1024|2048|4096} indicates block size

-L "Label" volume label

-j: Log, equivalent to-t ext3

-I #: Create an inode for each number of bytes in the data space, should not be small block size,

Blkid: Viewing block device property information

E2label: lable # E2label Device for managing EXT Series File Systems

TUNE2FS: Reset the values of the EXT series file system adjustable parameters

-L: View information for the specified file system super block

-L: Modify the volume label

DUMPE2FS:-H View Super block information

Mkswap: Creating Swap partitions

-L:

File System Detection:

Fsck:file System Check

-T Fs_type: detects a specific file system and must be the same as the file type already on the partition

-A: Auto fix error

-R: Interactive Repair

E2fsck:ext Series special detection and Repair tool

-F: Forced repair

-Y: Auto Answer Yes

File System Management:

Establish a relationship between an additional file system and an existing directory of the root filesystem, which can be used as an entry for other files, Mount

Disassociate relationship Offload

Associate Device mount point: Mount,

When uninstalling, you can use the device, or you can use the mount point Umount

Note: The existing files under mount point will be temporarily hidden after the mount is completed

Mount method: Mount DEVICE Mount_point

Mount: Displays all devices that are already mounted on the current system

Device: Indicates which devices to mount

(1): Device files: e.g./dev/sda3

(2): Volume Label:-L "Label" such as-L "mydate"

(3): UUID:-U "UUID" for example:-U ""

(4): Pseudo file system name: Proc, SYSFS, Devtmpsfs, Configfs

Dir: Mount point

Pre-existing: Recommended use of empty directory

The device in process use cannot be uninstalled

Common options:

-T Vsftype: Specifies the type of file system on the device you want to mount

-r:readonly: Read-only Mount

-w:read and write read-write mount

-N: Do not update/etc/mtab (track all mounts and uninstalls)

-A: Automatically mounts all devices that support automatic mounts (defined in the/etc/fstab file, with the "Auto Mount" feature in the Mount option)

-V: Show Mount Process

View all mounted devices tracked by the kernel: cat/proc/mounts

-O Options:

Async: Async Mode

Sync: Synchronous mode

Atime/noatime: Synchronization timestamp (default Notaime) (contains directories and files)

Diratime/nodiratime: Access timestamp for directory

Auto/noauto: Whether auto-mount default auto is supported

Exec/noexec: Whether to support running applications on the file system as a process

Uninstall command:

Umount DEVICE

Umount Mount_point

See who is using the mount point fuser-v/mydate/fuser-km/mydate/Delete user

Mount Swap partition:

Enabled: Swapon

-A: Activate all swap partitions

-P Priority: Specify precedence

Disabled: Swapoff

Memory space usage Status: free-m or-G

File Space Usage Status View tool: Df-h or-iinode Usage-p uses POSIX format output

View the overall space consumption status of a directory

Du disk useage

Du Dir-h-S: Show total size

File Mount Profile:/etc/fstab

Each row defines a file system to mount

Device to mount or pseudo file system mount point file System type Mount options dump frequency self-test order

Link file:

Hard Links: cannot be done on the directory, not across partitions

Multiple different paths to an inode, creating a hard link to a file creates a new reference path for the inode, thus increasing its reference count

Symbolic Links: You can make a directory, cross-partition, point to the path of another file, whose size is the length of the path string, without increasing or decreasing the reference count of the target file Inode

ln [-SV] SRC dest-s: Soft Connection

Impact of file management operations on files

File Delete: File reference count is 0, idle

File copy: Creates a new empty file and populates the data with the new empty file. Involves read-out and write

File move: Copy and delete, path change (just move the reference path of the original data)

This article is from the "Vulcan and Fire" blog, make sure to keep this source http://notezr.blog.51cto.com/9424982/1918968

Linux Disk Management