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Dante
Asked: 2021-01-03 06:40:48 +0800 CST

fstab automatically creates mount points

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As mentioned here, "you must create the mount point before you mount the partition." But after adding the following lines in fstab and rebooting the system

/dev/sdxy /media/user/hdd_mount_point ext4 defaults 0 0
tmpfs /mnt/tmpfs_mount_point tmpfs rw,nosuid,noatime,nodev,size=4G,mode=1777 0 0

the mount points (target directories) hdd_mount_point and tmpfs_mount_point are automatically created if they do not exist. I know that you can make a mount point if it does not exist by adding the X-mount.mkdir option to mount command as mentioned in its manual page, but I really like to know if this option is implicitly used when mounting file systems via fstab.

And NO, it is not a duplicate of Automatic Adding of Filesystems to /etc/fstab

fstab

2 Answers

  1. This used to be true, and still is if you wish to use the classic mount command.

    In recent years, the entries in /etc/fstab are mounted at boot time by systemd, which automatically creates missing mountpoints as needed, irrespective of the presence of the X-mount.mkdir option.

    It also provides the command systemd-mount as an alternative to mount, should you wish to mount a partition yourself without first manually creating a directory to mount over.

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  2. Best Answer

    And here the essential parts from the documentation:

    Mount units may either be configured via unit files, or via /etc/fstab
(see fstab(5) for details). Mounts listed in /etc/fstab will be converted
into native units dynamically at boot and when the configuration of the
system manager is reloaded. In general, configuring mount points through
/etc/fstab is the preferred approach. See systemd-fstab-generator(8) for
details about the conversion.

    Further down you'll find this:

    Where=

    Takes an absolute path of a file or directory for the mount point;
    in particular,the destination cannot be a symbolic link. If the
    mount point does not exist at the time of mounting, it is created
    as directory.
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