Identify the persistent identifiers of block devices so mounts and fstab remain stable across reboots. 13.02.2026 | reading time: 2 min When disks move or device names change, the filesystem UUID stays the same; this lesson shows how to display those UUIDs so mounts, fstab entries and systemd units keep working reliably. Try this on a lab VM Run the commands shown below to inspect UUIDs and see real output; this example uses `lsblk`, `blkid` and `findmnt` in sequence to locate the UUID of the root partition: ``` $ lsblk -f NAME FSTYPE LABEL UUID MOUNTPOINT sda ├─sda1 ext4 3b1f9c2e-4a5b-6c7d-8e9f-0123456789ab / ├─sda2 swap e2d2f3a4-5b6c-7d8e-9f01-23456789abcd [SWAP] └─sda3 ext4 9a7b6c5d-4e3f-2b1a-0987-fedcba654321 /data $ blkid /dev/sda1 /dev/sda1: UUID="3b1f9c2e-4a5b-6c7d-8e9f-0123456789ab" TYPE="ext4" PARTUUID="11111111-2222-3333-4444-555555555555" $ findmnt -no UUID / 3b1f9c2e-4a5b-6c7d-8e9f-0123456789ab ``` When to prefer UUIDs Use UUIDs in `/etc/fstab` and systemd mount units when device node names like `/dev/sda1` might change, and prefer `findmnt -no UUID <mountpoint>` to script lookups; remember `blkid` may need root, some filesystems set UUIDs at format time, and cloning disks requires regenerating UUIDs to avoid duplicate identifiers. Commands worth knowing Besides `lsblk`, `blkid` and `findmnt` you will often use `udevadm info` to query udev attributes, `tune2fs -U` to change ext-family UUIDs, and `cryptsetup` for LUKS devices where both the container and the inner filesystem can have identifiers; combine them to diagnose boot problems or fstab mismatches. Keep mounts predictable Make a habit of referencing UUIDs for critical mounts so kernels and init systems find the right volumes even if device names shift; if you want to deepen system knowledge and prepare for certification, explore LINUX exam training such as CompTIA Linux+ or LPIC-1 with intensive courses at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. filesystem utilities storage boot-process troubleshooting
