Inode exploration and the relationship between Inode and soft link and hard link

I. Documentation system-related knowledge

Superblock: Records The overall properties of this file system, including the total amount of inode/block, usage, amount remaining, and file system format and related information

Block: Record the contents of the file, if the file is too large, occupy multiple blocks

Inode: Record file properties, one file occupies one inode

The file system is generally divided into block groups (blocks group), each block group has superblock, file system description, block correspondence table, inode correspondence table, Inodetable,dateblock composition

1. (1) block size is not changed after formatting, unless reformatted

(2) Each block can only put one file of data

(3) block size has 1KB,2KB,4KB

2,. (1) inodetable is used to record the attributes of the file and the file is actually placed within the block

(2) Inode recording a block requires 4bytes

(3) Inode up to 12 direct points

(4) different file system inode size is not the same,

3.File System Description: Describes block numbers starting and ending for each block group

4.block Bitmap (Fast table): Used to modify block status in real time

5.inode Bitmap (inode table): Log used and unused inode codes

DUMP2FS Backup, view file system Information

Two. Soft links and hard links
ln source destination default is to establish a hard link

Ln-s source destination Creating soft links

1. Hard links use detailed,

(1) Create a hard link to the/etc/crontab/root/crontab

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The number of links found increases by 1 and the remaining properties are unchanged

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(2) Hard link cannot cross file system, cannot connect directory

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2. Detailed use of soft links

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When you create a soft connection, the so-called relative path is relative to the linked file, not the directory

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Inode exploration and the relationship between Inode and soft link and hard link