/etc/mtab and /etc/fstab Files

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∟/etc/mtab and /etc/fstab Files

This section provides a quick introduction on /etc/mtab and /etc/fstab. One holds currently mounted file systems. The other holds file systems to be mounted at boot time.

There are two system files on a Linux computer that hold important information about file systems: /etc/mtab and /etc/fstab.

What Is /etc/mtab File? /etc/mtab is a system file that contains a list of currently mounted file systems and their mounting parameters.

For example, here is what I have in /etc/mtab on my Ubuntu computer.

herong$ head /etc/mtab

rootfs / rootfs rw 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
tmpfs /dev tmpfs rw,nosuid,size=65536k,mode=755 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,ptmxmode=666 0 0
sysfs /sys sysfs ro,nosuid,nodev,noexec,relatime 0 0
cgroup /sys/fs/cgroup/pids cgroup ro,nosuid,nodev,noexec,relatime,pids 0 0
shm /dev/shm tmpfs rw,nosuid,nodev,noexec,relatime,size=65536k 0 0
/dev/sda6 /boot ext4 rw,seclabel,relatime 0 0
//192.168.1.6/share /mnt/share cifs rw,relatime,vers=3.1.1,cache=strict,...
nsfs /run/docker/netns/bfb24f16e35e nsfs rw,seclabel 0 0
...

What Is /etc/fstab File? /etc/fstab is a system file that contains a list of definitions of file systems to be mounted automatically at boot time.

For example, here is what I have in /etc/fstab on my Ubuntu computer.

herong$ head /etc/fstab

UUID=bfb24f1-...      /boot       ext4    defaults        1 2
/dev/mapper/cl-root   /           xfs     defaults        0 0
/dev/mapper/cl-home   /home       xfs     defaults        0 0
/dev/mapper/cl-swap   swap        swap    defaults        0 0
UUID=04904a81-...     /mnt/data   ext4    rw,seclabel     0 0
file-server:/export   /mnt/file   nfs     defaults        0 0
tmpfs                 /var/tmp    tmpfs   gid=nobody,..   1 0