Fstab document presents
fstab file contains the information storage device and file system on your computer. It is a hard decision (partition) is how to use or integrated into the overall system files. Specifically: Use fstab to automatically mount the various file system formats the hard disk partition, removable devices and the remote equipment. For Windows and Linux dual operating system user with fstab to mount FAT format and NTFS formatted partitions, windows system can share resources in Linux.
The full path of this file is / etc / fstab. It's just a text file, you can open it with your favorite editor, but it must be the root user to edit it. Meanwhile fsck, mount, umount such orders the use of the program.
/ Etc / fstab configuration file at start-up, however, the actual filesystem mount is recorded in / etc / mtab and / proc / mounts among these two files. Every time when we mount filesystem changes, changes of these two documents will also Oh!
Some restriction system mounted:
/ Is to be mounted, and must first be mounted to other mount point came.
Other mount point must be a directory that has been created, can be specified, but must comply with the principle of the necessary system directory structure
All mount point at the same time, the mount only once.
All partition at the same time, the mount only once.
Should be dismounted, you must first move outside the working directory mount point (and its subdirectories).
File of each field
# < Fs> < mountpoint> < type> < opts> < dump / pass>
# NOTE: If your BOOT partition is ReiserFS, add the notail option to opts.
/ Dev / sda10 / boot ext4 noauto, noatime 1 2
/ Dev / sda6 / ext4 noatime 0 1
/ Dev / sda9 none swap sw 0 0
/ Dev / cdrom / mnt / cdrom auto noauto, ro 0 0
In fact, when / etc / fstab (filesystem table) that we will use the mount command, writes all of the options and parameters to the file you want. In addition, / etc / fstab also added support for the dump backup command! And whether the file system check fsck commands at startup related.
< File systems> Mounting equipment: not our usual understanding of the file system, but rather refers to the equipment (hard disks and partitions, DVD drive, etc.). It tells us the device (partition) name, which is when you mount (mount) command line, unloading (umount) to use the equipment.
< Mountpoint> mount point: Tell us where to mount the device.
< Type> file system types: Linux supports many file system. To get a complete list of supported lookup mount man-page. Typical of these names include: ext2, ext3, reiserfs, xfs, jfs, iso9660, vfat, ntfs, swap and auto, 'auto' is not a file system, but to mount command to automatically determine the file type, especially for mobile devices, floppy disk, DVD drive, this is necessary, because it may not match each mounted file types.
< Opts> file system parameters: This section is the most useful settings! ! ! It enables you to mount the device automatically loaded at boot time, so do not display Chinese garbled, limit mount the partition read and write permissions. It is related to usage and mount command, in order to get a complete list, refer to mount manpage.
< Dump> Backup command: dump utility to decide whether to make a backup dump checks the entry and use the numbers to determine whether the file system backups. The allowed number is 0 and 1. If 0, dump will ignore the file system, and if 1, dump will make a backup. Most users do not have dump, so for them < dump> This entry should be written to zero.
< Pass> fsck to verify whether the sector: the boot process, the system will default to test our fsck filesystem is complete (clean). However, some test filesystem is not required, such as the replacement of memory space (swap), or a special file systems such as / proc and / sys, and so on. fsck checks at the head of this figure to determine the order check the file system, allowing the number is 0, 1, and 2.0 is not inspection, 1 represents the first test (usually only the root directory is configured to 1), also to 2 test, but will be relatively long been a test it! In general, the root directory is configured to 1, the other to test the filesystem are configured as 2 just fine.
< Opts> common parameters:
noatime close atime features to improve performance, which is a very old property, closed at ease, but also reduce loadcycle
defaults using the default settings. Equal rw, suid, dev, exec, auto, nouser, async, see the specific meaning explained below.
Automatic and manual mounting:
auto mounted automatically at boot or enter the mount -a in a terminal
noauto device (partition) can be manually mounted
Read and write permissions:
ro mounted as read-only access
rw mount read-write permissions
exec is the default settings, it makes an executable binary files in that partition can be performed
noexec binary file is not allowed. Never in your root partition using this option! ! !
I / O synchronization:
sync All I / O will be performed synchronously
async All I / O will be performed asynchronously
Household mount privileges:
user allows any user to mount devices. Implies noexec, nosuid, nodev unless overridden.
nouser only allow root user to mount. This is the default setting.
Temporary file execute permission:
suid Permit the operation of suid, and sgid bits. They are mostly used to allow users on a computer system to execute binary executables with temporarily elevated privileges in order to perform a specific task.
nosuid Blocks the operation of suid, and sgid bits.
Reboot the system
Reboot the system, or enter the mount -a in a terminal can see the effect of the modified.