最後更新: 2020-08-22

介紹

An ext4 file system is split into a series of block groups.

To reduce performance difficulties due to fragmentation,

the block allocator tries very hard to keep each file's blocks within the same group,

thereby reducing seek times.

The size of a block group is specified in sb.s_blocks_per_group blocks, though it can also calculated as 8 * block_size_in_bytes.

With the default block size of 4KiB, each group will contain 32,768 blocks, for a length of 128MiB.

The number of block groups is the size of the device divided by the size of a block group.

All fields in ext4 are written to disk in little-endian order. HOWEVER,

  all fields in jbd2 (the journal) are written to disk in big-endian order.

Files Basic Backup
Support for basic file attributes (permissions, owner, ...)
Support for extended attributes (SELinux)
Everything is checksummed (loose the current file)
basic file-system attributes (label, uuid, block-size)
Multi-threaded lzo, gzip, bzip2, lzma compression
splitting large archives into several files
Encryption of the archive using a password
restore the filesystem to a partition which is smaller than the original
restore the data on a different file-system
It allows to preserve all the windows file attributes (ACL, standard attributes, ...).

Example

最後更新: 2020-07-26

介紹

resize2fs - ext2/ext3/ext4 file system resizer

目錄

• Expand with parted
• resize2fs
• 減容量(LVM)

最後更新: 2021-08-23

介紹

super-server: only daemon process started and it listens on all service ports for the services

multi-threaded: forking of a new server process for each new connection request

single-threaded: xinetd will stop handling new requests for them until the server dies.