Linux operation and Maintenance system Engineer Series---18

Disk Management

Simple overview

File system
A method of organizing files on disk, called a file system.

Ext3 EXT4 Differences:
Ext3 maximum support is 16TB file system, maximum 2TB files, support up to 32,000 subdirectories
EXT4 supports 1EB file system, 1EB=1024PB,1PB=1024TB,1TB=1024GB
Maximum 16TB files.
Inode-related features, EXT4 support for larger inode, more than ext3 128 bytes, ext4 default 256 bytes, so the inode contains more extended attributes (such as nano-scale timestamp, etc.)

Superblock: Super block, which records the overall information of the file system, including the number of Inode/block, the amount of usage, the amount of remainder, the format of the file system, and related information.

Inode: Records a variety of file information, file size, permissions, I node number, time, and so on. Plainly, some of the properties of the file
I--index

Block: A block of data that records the true contents of a file, which can occupy multiple blocks of data.

The I node of the directory records the I node number corresponding to the file name and file name of the directory.

viewing file System Information
[[email protected] proc]# dumpe2fs-h/dev/sda2 only header information displayed
DUMPE2FS 1.41.12 (17-may-2010)
Filesystem volume Name: <none>//Names of file systems
Last mounted on:/
Filesystem uuid:41986717-b65d-4dcb-82a7-bec24c9b5649
Filesystem Magic number:0xef53
Filesystem Revision #: 1 (dynamic)
Filesystem features:has_journal ext_attr resize_inode dir_index filetype needs_recovery extent FLEX_BG Sparse_su Per large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem Flags:signed_directory_hash
Default mount Options:user_xattr ACL//Defaults mount parameter
Filesystem State:clean//clean says this filesystem is no problem.
Errors behavior:continue
Filesystem OS Type:linux
Inode count:1310720 Total number of//i nodes
Block count:5242880//Total number of data blocks
Reserved block count:262144//reserved space for root
Free blocks:4664077//number of blocks left
Free inodes:1236372//Remaining I-node points
First block:0
Block size:4096//chunk size
Fragment size:4096
Reserved GDT blocks:1022
Blocks per group:32768
Fragments per group:32768
Inodes per group:8192
Inode blocks per group:512
Flex Block Group Size:16
Filesystem created:wed Oct 9 16:08:55 2013
Last Mount Time:wed Oct 9 16:33:25 2013
Last Write time:wed Oct 9 16:32:54 2013
Mount Count:2
Maximum Mount Count: 1
Last checked:wed Oct 9 16:08:55 2013
Check interval:0 (<none>)
Lifetime writes:3086 MB
Reserved blocks uid:0 (user root)
Reserved blocks gid:0 (group root)
First Inode:11
Inode size:256
Required Extra isize:28
Desired extra isize:28
Journal Inode:8
First Orphan inode:943377
Default Directory HASH:HALF_MD4
Directory Hash seed:5941779c-7722-46dd-acb1-ab375fe7f29f
Journal Backup:inode Blocks
Journal Features:journal_incompat_revoke
Journal size:128m
Journal length:32768
Journal Sequence:0x000036ee
Journal start:27664

This article is from the "Empty Valley Orchid" blog, please be sure to keep this source http://2489843.blog.51cto.com/2479843/1669378

Linux operation and Maintenance system Engineer Series---18