Linux HDD Mount

1, first, we talk about the hard drive.

We all know that hard disk is used to store files, of course, with the file system (file system management of the corresponding hardware resources).

A hard disk consists of multiple disks, each with two sides, a head on each side, and multiple tracks on the disk.

The hard disk is divided into several sectors, the current normal one sector is 512byte. The first sector stores the master boot record and the partition table information.

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HDD Storage capacity = number of Heads x track (cylinder) x number of sectors x per sector × bytes per slice

(1) The hard disk has several platters, two faces per platter, one head per face

(2) The disc is divided into a plurality of sector sectors i.e. sector

(3) Concentric circles with different radii of the same disc as track

(4) cylindrical surface with same radius of different discs

(5) formula: Storage capacity = number of Heads x track (cylinder) x number of sectors per sector X number of bytes per sector

(6) Information record can be expressed as: xx track (cylinder), XX Head, XX sector

2. HDD partition and Mount under Linux

2.1 Everything is in the form of a document

In Linux, all the devices are in the form of files, including hard drives.

The device file path in the/dev path. For example, there is a hard disk SDA in the machine. Coexist in partition Sda1,sda2,sda5.

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The other/path is the root path of the Linux system.

Below the machine, the SDA1 partition is mounted under the root path, and the partition is 85G in size.

[Email protected]:/dev$ df-h

Filesystem Size used Avail use% mounted on

Udev 982M 4.0K 982M 1%/dev

Tmpfs 199M 1.7M 197M 1%/run

/DEV/SDA1 85G 23G 58G 29%/

None 4.0K 0 4.0K 0%/sys/fs/cgroup

None 5.0M 0 5.0M 0%/run/lock

None 992M 144K 992M 1%/RUN/SHM

None 100M 36K 100M 1%/run/user

2.2 Adding and partitioning a hard drive

We have an example of this machine

The machine is a virtual machine built on Windows using VMware, Ubuntu system.

First we add the hard drive, and then we need to reboot.

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After adding, we can see the newly added hard disk device in/dev:/dev/sdb

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2.3 Hard Disk partitions

After finding the newly added hard disk file (/DEV/SDB), we need to partition it

[Email protected]:/dev$ sudo fdisk SDB

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF Disklabel

Building a new DOS disklabel with disk identifier 0x1fc07a59.

Changes'll remain in memory only, until the decide to write them.

After that, of course, the previous content won ' t is recoverable.

Warning:invalid flag 0x0000 of partition Table 4 would be a corrected by W (rite)

Command (M for help): M

Command Action

A toggle a bootable flag

b Edit BSD Disklabel

C Toggle the DOS compatibility flag

D Delete a partition

L list known partition types

M Print this menu

n Add a new partition

o Create a new empty DOS partition table

P Print the partition table

Q Quit without saving changes

s create a new empty Sun Disklabel

t change a partition ' s system ID

U Change display/entry units

V Verify the partition table

W Write table to disk and exit

X Extra functionality (experts only)

Command (M for help): P

Disk sdb:5368 MB, 5368709120 bytes

255 heads, Sectors/track, 652 cylinders, total 10485760 sectors

Units = sectors of 1 * MB = bytes

Sector size (logical/physical): bytes/512 bytes

I/O size (minimum/optimal): bytes/512 bytes

Disk identifier:0x1fc07a59

Device Boot Start End Blocks Id System

Command (M for help): N

Partition Type:

P Primary (0 primary, 0 extended, 4 free)

E Extended

Select (default p): P

Partition number (1-4, default 1): 1

First sector (2048-10485759, default 2048):

Using Default Value 2048

Last sector, +sectors or +size{k,m,g} (2048-10485759, default 10485759): +2g

Command (M for help): W

The partition table has been altered!

Calling IOCTL () to re-read partition table.

Syncing disks.

The above procedure we added a 2Gbyte partition sdb1

Above we notice that the partition number can only be 1~4, because:

We talked before. The first sector stores the master boot record and the partition information,

The master boot record needs 446byte, each partition information needs 16byte, and a sector is only 512byte,

therefore (512-446)/16----4 maximum of 4 partitions.

Of course, we can choose to use 3 primary partition to add an extended partition method, the extended partition can create an infinite number of logical partitions.

For example, after partitioning we can find the partition file/dev/sdb1

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2.4 Formatting partitions

We formatted/DEV/SDB1 as EXT4 (Ext4 is one of the file system formats)

[Email protected]:/dev$ mkfs.ext4/dev/sdb1

MKE2FS 1.42.9 (4-feb-2014)

Mkfs.ext4:Permission denied while trying to determine filesystem size

[Email protected]:/dev$ sudo mkfs.ext4/dev/sdb1

MKE2FS 1.42.9 (4-feb-2014)

Filesystem label=

OS Type:linux

Block size=4096 (log=2)

Fragment size=4096 (log=2)

Stride=0 blocks, Stripe width=0 blocks

131072 inodes, 524288 blocks

26214 blocks (5.00%) reserved for the Super user

First Data block=0

Maximum filesystem blocks=536870912

Block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

32768, 98304, 163840, 229376, 294912

Allocating group Tables:done

Writing Inode Tables:done

Creating Journal (16384 blocks): Done

Writing superblocks and filesystem accounting Information:done

2.5 Mount Partition

Mounting is roughly understood to hook up a storage device with a path.

Mount partitions can be mounted temporarily using mount, or you can modify the fstab directly to mount them.

2.5.1 Mount Temporary Mount

Mount temporarily mounts a device that is no longer mounted after rebooting the system. Files created and written during Mount are not lost.

[Email protected]:~$ mkdir Mynewdisk

[Email protected]:~$ ls

Bin Desktop Documents Downloads examples.desktop Music myLearn mynewdisk Pictures public Templates Videos work S

[Email protected]:~$ sudo mount/dev/sdb1 ~/mynewdisk

When mounted

[Email protected]:/dev$ df-h

Filesystem Size used Avail use% mounted on

Udev 982M 4.0K 982M 1%/dev

Tmpfs 199M 1.7M 197M 1%/run

/DEV/SDA1 85G 23G 58G 29%/

None 4.0K 0 4.0K 0%/sys/fs/cgroup

None 5.0M 0 5.0M 0%/run/lock

None 992M 144K 992M 1%/RUN/SHM

None 100M 36K 100M 1%/run/user

/DEV/SDB1 2.0G 3.1M 1.8G 1%/home/jetxu/mynewdisk

This allows us to use the newly added hard drive resources. The operation on the/home/jetxu/mynewdisk path is based on the newly added hard drive.

2.5.2 Permanent Mount

Add the following to the/etc/fstab file.

/dev/sdb1/home/jetxu/mynewdisk EXT4 Defaults 0 0

[Email protected]:/dev$ cat/etc/fstab

#/etc/fstab:static File System information.

#

# use ' Blkid ' to print the universally unique identifier for a

# device; This is used with uuid= as a more robust-to name devices

# that works even if disks is added and removed. See Fstab (5).

#

# <file system> <mount point> <type> <options> <dump> <pass>

#/was on/dev/sda1 during installation

UUID=1664B5BB-45E6-43F5-BFE7-3AE34CCAA6AC/EXT4 Errors=remount-ro 0 1

# Swap was on/dev/sda5 during installation

Uuid=e714a2eb-4856-4081-893f-29bd947a3dc2 None swap SW 0 0

/dev/fd0/media/floppy0 Auto Rw,user,noauto,exec,utf8 0 0

/dev/sdb1/home/jetxu/mynewdisk EXT4 Defaults 0 0

After reboot (boot process system automatically mounts)

[Email protected]:/dev$ df-h

Filesystem Size used Avail use% mounted on

Udev 982M 4.0K 982M 1%/dev

Tmpfs 199M 1.7M 197M 1%/run

/DEV/SDA1 85G 23G 58G 29%/

None 4.0K 0 4.0K 0%/sys/fs/cgroup

None 5.0M 0 5.0M 0%/run/lock

None 992M 144K 992M 1%/RUN/SHM

None 100M 32K 100M 1%/run/user

/DEV/SDB1 2.0G 3.1M 1.8G 1%/home/jetxu/mynewdisk

Linux HDD Mount