Understanding the function of FSTAB in linux

Understanding the function of  FSTAB in linux.
fstab is a file startup boot that to present when system is bootup.

Example 1 :-

 

# /etc/fstab: static file system information.

#

# <file system> <mount point>   <type>      <options>           <dump>     <pass>

  proc            /proc           proc    defaults                  0       0

 /dev/sda2       /               ext3    defaults,errors=remount-ro 0       1

 /dev/sda1       /boot           ext3    defaults                   0       2

 /dev/hdc        /media/cdrom0   udf,iso9660 user,noauto            0       0

 /dev/fd0        /media/floppy0  auto    rw,user,noauto             0       0

 /dev/fileserver/share   /var/share     ext3       rw,noatime       0       0

 /dev/fileserver/backup    /var/backup      xfs        rw,noatime   0       0

 /dev/fileserver/media    /var/media      reiserfs   rw,noatime     0       0

# device name   mount point     fs-type      options                                        <dump> <pass>

 LABEL=/         /               ext4         defaults                                           1 1
/dev/sda6       swap            swap         defaults                                            0 0
none            /dev/pts        devpts       gid=5,mode=620                                      0 0
none            /proc           proc         defaults                                            0 0
none            /dev/shm        tmpfs        defaults                                            0 0
 
# Removable media
/dev/cdrom      /mnt/cdrom      udf,iso9660  noauto,owner,ro                                     0 0
 
# NTFS Windows 7 partition
/dev/sda1       /mnt/Windows    ntfs-3g      quiet,defaults,locale=en_US.utf8,umask=0,noexec     0 0
 
# Partition shared by Windows and Linux
/dev/sda7       /mnt/shared     vfat         umask=000                                           0 0
 
# mounting tmpfs
tmpfs           /mnt/tmpfschk   tmpfs        size=100m                                           0 0
 
# mounting cifs
//pingu/ashare  /store/pingu    cifs         credentials=/root/smbpass.txt                       0 0
 
# mounting NFS
pingu:/store    /store          nfs          rw                                                  0 0

***note ***note*** note *** !!!

dump-freq adjusts the archiving schedule for the partition (used by dump).

pass-num<pass> Controls the order in which fsck checks the device/partition for 

               errors at boot time. 

               The root device should be 1. Other partitions should be either ;

               2(to check after root) or

               0 (to disable checking for that partition altogether). 

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The options common to all filesystems are:

atime / noatime / relatime / strictatime (Linux-specific)

The Unix stat structure records when files are last accessed (atime), modified (mtime), and changed (ctime). One result is that atime is written every time a file is read, which has been heavily criticized for causing performance degradation and increased wear. However, atime is used by some applications and desired by some users, and thus is configurable as atime (update on access), noatime (do not update), or (in Linux) relatime (update atime if older than mtime). Through Linux 2.6.29, atime was the default; as of 2.6.30 (9 June 2009), relatime is the default.^[1]

auto / noauto

With the auto option, the device will be mounted automatically at bootup or when the mount -a command is issued. auto is the default option. If you do not want the device to be mounted automatically, use the noauto option in /etc/fstab. With noauto, the device can be only mounted explicitly.

dev / nodev

Interpret/do not interpret block special devices on the filesystem.

exec / noexec

exec lets you execute binaries that are on that partition, whereas noexec does not let you do that. noexec might be useful for a partition that contains no binaries, like /var, or contains binaries you do not want to execute on your system, or that cannot even be executed on your system. Last might be the case of a Windows partition.

ro

Mount read-only.

rw

Mount the filesystem read-write. Again, using this option might alleviate confusion on the part of new Linux users who are frustrated because they cannot write to their floppies, Windows partitions, or other media.

sync / async

How the input and output to the filesystem should be done. sync means it is done synchronously. If you look at the example fstab, you will notice that this is the option used with the floppy. In plain English, this means that when you, for example, copy a file to the floppy, the changes are physically written to the floppy at the same time you issue the copy command.

suid / nosuid

Permit/Block the operation of suid, and sgid bits.

user / users / nouser

user permits any user to mount the filesystem. This automatically implies noexec, nosuid, nodev unless overridden. If nouser is specified, only root can mount the filesystem. If users is specified, every user in group users will be able to unmount the volume.

owner (This is Linux-specific)

Permit the owner of device to mount.

defaults

Use default settings. Default settings are defined per file system at the file system level. For ext3 file systems these can be set with the tune2fs command. The normal default for Ext3 file systems is equivalent to rw,suid,dev,exec,auto,nouser,async(no acl support). Modern Red Hat based systems set acl support as default on the root file system but not on user created Ext3 file systems. Some file systems such as XFS enable acls by default. Default file system mount attributes can be overridden in /etc/fstab.