How to Auto-Mount File Systems on Startup in RedHat Linux

Linux systems often require manual configurations, especially for mounting disks. This guide walks you through the process of configuring the fstab file on RedHat servers to auto-mount file systems or drives (e.g., external disks, USBs) at startup.

Understanding the fstab File

The fstab (file system table) is located in the /etc directory on Unix-like systems. It lists available disk partitions and other file systems, specifying how they are integrated into the larger file system structure.

Here’s an example of an fstab file:

#/etc/fstab
# Created by anaconda on Wed Nov 16 18:06:51 2022
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
/dev/mapper/rhel-root   /                       xfs     defaults        0 0
UUID=cee77f86-bf0a-4039-88f4-2c01361a392f /boot                   xfs     defaults        0 0
UUID=6B73-F145          /boot/efi               vfat    umask=0077,shortname=winnt 0 2
/dev/mapper/rhel-home   /home                   xfs     defaults        0 0
/dev/mapper/rhel-swap   none                    swap    defaults        0 0

Key components of fstab entries:

• File system identifier: Can be a UUID or a label.
• Mounting point: Directory where the file system will be accessible.
• File system type: Types like xfs, vfat, swap, ext4, etc.
• Mount options: Commonly defaults (rw, suid, dev, exec, auto, nouser, async).
• Dump value: Specifies backup frequency (0 = no backup).
• Pass value: Order for checking file systems at boot (0 = no check, 1 = first, 2 = second).

Adding a New File System to fstab

To auto-mount a new SSD on your server:

• Identify the File System Use the blkid command to get the UUID:

[root@kvm ~]# blkid

Example output:

/dev/sdc1: LABEL="SSD1" UUID="77f8b83f-2941-433d-8c3e-547940113ad5" TYPE="ext4"

• Create a Mount Point Create a directory for the new file system:

[root@kvm ~]# mkdir /newfilesystemfolder

• Edit the fstab File Open fstab for editing:

[root@kvm ~]# nano /etc/fstab

• Add the new entry:

UUID=77f8b83f-2941-433d-8c3e-547940113ad5 /newfilesystemfolder ext4 defaults 0 0

• Mount the File System Mount all file systems listed in fstab:

[root@kvm ~]# mount -a

• Verify the file system is mounted using the df command:

[root@kvm ~]# df -h

Important Notes:

• Always backup your fstab file before editing.
• To unmount a file system, use:

[root@kvm ~]# umount /dev/sdd2

After these configurations, you can safely reboot your server to ensure the settings take effect.

This article was first published in December 2023. checkout the original version here: https://archives.genzis.net/blog/set-up-file-systems-to-auto-mount-on-startup-redhat-server