One: that the file system:
( 1): Linux system supports dozens of file systems, common are these types:
1: Ext3: is a journaling file system, the file system can avoid data loss when the system is abnormal downtime and can automatically fix inconsistencies and erroneous data. However,
when a large hard drive capacity, required repair time will be very long, and can not guarantee 100% data is not lost.
2: Ext4: an improved version of Ext3, as the default RHEL 6 system document management system, which supports a storage capacity of up to 1EB (1EB = 1 073741 824GB) ,
and can have an unlimited number of subdirectories. Further, Ext4 file system can allocate block block quantities, thereby greatly enhancing the efficiency of reading and writing.
(2): The XFS file system:
. 1: XFS: is a high performance file system log, and RHEL 7 is the default file management system.
2: Hard disk data to be stored in three very large, so there is a place called super block (hard disk map) in the disk he recorded the entire file system information.
3: Super Block recording: Linux and the permissions for each file attribute recorded in the inode, and each occupies a separate file inode table default size of the table is 128 bytes.
4: The recorded information is:
• Access to the file (read, write, execute).
• owner and owning group (owner, group) of the file.
• The file size (size).
• Create or contents of the file modification time (ctime).
• The last access time (atime) for the file.
• modification time of the file (mtime).
Special privileges (SUID, SGID, SBIT) • files.
• address the real data file (point).
5: the contents of the file storage: When the inode after the storage, the contents of the file will be stored in one block of one block, the block size, there are several cases,
when a user wants to read a file, the system routes each block string together the user can read the complete file.
6: the case of block storage:
• Case 1: The file is very small (1KB), but still occupies one block, thus wasting 3KB.
• Scenario 2: very large file (5KB), it will take two block (after 5KB-4KB remaining 1KB have occupied a block)
II: Understanding the Linux file system directory structure:
(1): Introduction: In the Linux system , the directory, character device, block device, socket, printers and so became abstracted file: everything Linux file system, then we need to
we learn to look, to operate these files, the hard drive is in the window system there are divided, we often different content on different partitions and different file names.
but Linux is not the hard disk partition, all documents are in order (/) start at the root. And in accordance with the hierarchical file system standards (Filesystem Aierarchy Standard, FHS)
using a tree structure for files and directories defined in common use. In addition, Linux system file and directory names are strictly case-sensitive.