Linux file Systems (2)

Let's start by talking about the use of a disk:

The use of the disk must be formatted, the first to start with a low-level format, that is, dividing tracks, sectors and so on.

Later, you have to partition, create the file system, and then mount (that is, a directory associated to/below as the Access portal).

That is:

Low-level formatting (tracks, sectors)---> Partitioning---> Creating file Systems---> Mounting

Here, by the way, the root partition becomes the root partition (root filesystem), some directories are not independent

Out (such as/etc,/bin,/sbin, etc.)

To access a partition, you do not have to enter it from a directory under the root.

If/var/a/b can say/var on a partition, A is on partition 2nd and B is on partition 3rd.

To access partition 3rd, you need to access partition 1th and then access partition 2nd and then access the partition number 3rd.

So access to a partition is not directly or indirectly from/to the beginning.

Say the device file name of the hard disk device:

IDE, ATA: Starting with HD

SATA: Start with SD

SCSI: Start with SD

USB: Start with SD

A, B, c ..... Used to distinguish different devices under the same type

The IDE is unique and typically has only 2 IDE ports, with two disks per port

IDE: First IDE port: Master, from (HDA HDB)

Second IDE port: Master, Slave (hdc HDD)

1, 2, 3, 4, 5 ..... Used to flag partitions on a disk

Starting from 5 can only be logical partitions

Logical partitions can have multiple, extended partitions can only have one, primary partition up to 4

If you want to add a virtual hard disk, see the bottom picture of this blog post.

Here's the fdisk command:

Fdisk is the partitioning tool for Linux hard drives.

Usage: fdisk [-l] [device name]

Common usage: fdisk-l lists all disk devices and partition tables in the system

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The fdisk-l device names the partition table of the device

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fdisk device name to partition the device directly

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M Get help p displays the partition on the current hard disk

Q Do not save exit n Create new partition

W Save exit D Delete a partition

T modify the partition type L displays the supported file system types

The following is a brief demonstration of an operation to create a partition on/dev/sdb

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An operation that modifies the partition type

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Note: The above uses N to create a partition with P and E for selection (p stands for creating primary partition, E for creating extended partition)

Start cylinder can be directly enter

size words: +n (g| m| K)

Be sure to save with W after modifying.

You can use cat/proc/partitions to see if you have synced to the kernel after you modify it

If it is not synchronized to the kernel, it can be restarted, or partx-a the device name .

when deleting a partition, make sure that the partition is not used, to see if the partition is being used,

Can be viewed with df-h.

Create partitions with scripts (using Echo and | ）

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Add a virtual disk to the Linux host in the VM:

As shown in the right script, note that/DEV/SDB is a blank disk

The result is a 3 primary partition, and the 3rd primary partition is the swap partition.

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Click Add Directly

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Here the mouse clicks on the hard drive and then next

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Select the type of disk you want and then next

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Just go straight to the next line.

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Set the disk size yourself and then the next step

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Direct Click to finish

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Restart the system at this time

Can be viewed with fdisk-l after reboot

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Linux file Systems (2)