linuxexpert-practice-labs/labs/linux-terminal/2-2-partitions-and-filesystems/README.md

Using Linux Terminal 2.2: Partitions and filesystems

A GPT partition with an ext4 filesystem mounted at boot by UUID, getting a deleted partition back, and a read-only filesystem check.

Before you start

Work as root (sudo -i), and write answers to the files in /root/lab-answers/. The lab adds a blank 2 GiB spare disk, /dev/loop40, which stays attached across reboots; its first partition is /dev/loop40p1 (the guide's /dev/vdb and /dev/vdb1). It saves /etc/fstab and puts it back on reset, which also removes the disk.

Tasks

1. Give /dev/loop40 a GPT partition table with one 1 GiB partition, make an ext4 filesystem labeled data on it, and mount it at /mnt/data at every boot, by UUID. findmnt --verify reports no errors or warnings.
2. Save a file /mnt/data/keep.txt containing keep me. Unmount the filesystem, write its partition's start sector to /root/lab-answers/2, delete the partition with fdisk, then recreate it so that keep.txt comes back unchanged. Mount it again.
3. Check the filesystem fully while it's unmounted, without letting fsck change anything, and save fsck's output in /root/lab-answers/3.

Hints

• fdisk /dev/loop40 (g, n, +1G, w) or parted; mkfs.ext4 -L; blkid for the UUID; systemctl daemon-reload after editing fstab, then mount -a.
• fdisk -l /dev/loop40 shows the start; recreate with the same start and answer N to "remove the signature". fdisk asks that only at a terminal: fed from a pipe, it keeps the signature without asking. blkid shows the same UUID.
• fsck -fn /dev/loop40p1 >/root/lab-answers/3 2>&1.