Linux file system

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 is used to create a Linux file system on a device (usually a hard disk). The MKFS itself does not perform the work of establishing the filesystem, but rather calls the relevant program to execute it.

#文件系统创建命令 #

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MKFS (option) (parameter)

Options:

FS: Specifies the parameters when the file system is established;

-T < file system type;: Specifies what file system to build;

-V: Displays the version information and the detailed use method;

-V: Displays a brief use method;

C: Before making the file system, check whether the partition has bad track

(1) # MKFS. Fs_type /dev/device

Ext4

Xfs

Btrfs

Vfat

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

# mkfs-t fs_type-l ' LABEL '/dev/device

Set the volume label

Example:

First, create an XFS file system (if the XFS formatter discovers that a file system already appears on the partition, it will notify you.) Also note that the XFS format has been re-assigned the UUID)

Mkfs-t Xfs-i Size=512/dev/sda5

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Second, create a EXT4 partition

Mkfs-t ext4-l IAN-USB32/DEV/SDC1

(Use the-l option mkfs to label the partition and then use the Blkid command to display the GUID)

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Create ext File System

MKFS.EXT3 = mkfs-t ext3 = mke2fs-j = Mke2fs-t ext3

Mke2fs

Mke2fs:ext Series file system dedicated management tools, the "etc2/etc3" file system that was used to create the disk partition.

Command parameters:

1.-t {EXT2|EXT3|EXT4} specifies the file type

"Mke2fs-t EXT4/DEV/SDB5"

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2,-b {1024|2048|4096} specify block size

"Mke2fs-t ext4-b 8192/DEV/SDB6"

"Specifying a block size of 8192 indicates that the block value setting is too large, we directly type ' y ' to force formatting, and you can also try to specify a larger number. 】

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3,-l ' LABEL ' Set volume label

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4,-j: equivalent to-t ext3

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

-N #: Specify how many inode to create in a partition

-I an INODE record consumes disk space,---4096

-M #: Default 5%, Percentage of total space reserved for administrative staff

-O feature[,...] : Enable the specified attribute

-O ^feature: Turns off the specified attribute,

Device files: Specifies the partition device file name of the file system to be created;

Number of blocks: Specifies the number of disk blocks for the file system to be created.

File System Tags

Another method of pointing to a device is device Independent

Blkid Block Device properties Information View

Blkid [OPTION] ... [DEVICE]

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-U UUID: Find the corresponding device based on the specified UUID

-L Label: finds the corresponding device according to the specified label

E2label: Manage Label for ext series File system

# E2label DEVICE [LABEL]

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Findfs

Findfs: Finding partitions

Findfs [Options] label=<label> querying the file system based on the volume label

Findfs [Options] uuid=<uuid> querying the file system based on the UUID

Tune2fs

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

- L: View the specified file system super block information; Super block for a standalone file system. Save file system type, size, status, etc.)

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-L ' LABEL ': Modify volume label

-M #: Fixed percentage of space reserved for administrators

-j: Upgrade ext2 to Ext3

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-O: File System Properties enabled or disabled, –O ^has_journal

-O: Adjust default mount options for the file system, –o ^acl

-U uuid: Modifying the UUID number

Example:-U's parameter if clear indicates that the UUID of the file system is cleared

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Change the device to a specified UUID

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The-u parameter if the random indicates that a new UUID is directly generated:

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The-u parameter, if the time representation, produces a new UUID directly at the current moment:

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Set the number of times a file system can mount before forcing a check

Tune2fs-c 30/dev/hda1

To turn off forced check mount count limit

Tune2fs-c-l/dev/hda1

10 days after inspection

Tune2fs-i 10/dev/hda1

1 days after inspection

Tune2fs-i 1d/dev/hda1

3 weeks after inspection

Tune2fs-i 3w/dev/hda1

Six months later check

Tune2fs-i 6m/dev/hda1

Disabling time checking

Tune2fs-i 0/dev/hda1

Adjust the/DEV/HDA1 partition to a reserved space of 40,000 disk blocks

Tune2fs-r 40000/dev/hda1

Adjust the/DEV/HDA1 partition's reserved space to 10%

Tune2fs-m 10/dev/hda1

Set the/DEV/HDA1 mount option to enable POSIX Access Control lists and user-specified extended properties

Tune2fs-o acl,user_xattr/dev/hda1

Power-on cancel self-test

Tune2fs-l/DEV/SDB1 | Grep-e ' Maximum mount Count:|check interval '

Tune2fs-i 0-c 0/DEV/SDB1

DUMPE2FS: View File System Information: Superblock Information and block group information

-H: Do not show block group but only show Superblock and tune2fs-l consistent

Dumpe2fs-h = Tune2fs-l

File system detection and Repair

Conditions:

1) often occurs after the crash or abnormal shutdown

2) Mount for file system labeled "No clean"

Note: Be sure not to fix it in a mounted state

Fsck:file System Check

Fsck. Fs_type

Fsck-t Fs_type

-P: Auto Fix error

-r: Interactive fix error

Fs_type must be the same as the file type on the partition

E2fsck:ext series file-specific detection and repair tool

-Y: Auto Answer Yes

-F: Forced repair

Linux file system