LPIC-1 System Architecture Practice Test 4 — 15 Questions

Question 1

After modifying the /etc/fstab file, an administrator runs the command mount -a and receives the error 'mount: /data: special device /dev/sdb1 does not exist'. What is the most likely issue?

Accepted Answer

There is a typo in the device path in /etc/fstab.. The `mount -a` command reads all entries in /etc/fstab and attempts to mount them. The error 'special device /dev/sdb1 does not exist' indicates that the kernel cannot find the block device file at that path. The most likely cause is a typographical error in the device path within /etc/fstab, such as a misspelling (e.g., /dev/sdb1 vs /dev/sdb1) or an incorrect partition number, because the device file itself is created by udev and would exist if the hardware were properly detected.

Answer

The /dev/sdb1 device file is missing or corrupted.

Answer

The entry in /etc/fstab has an incorrect filesystem type.

Answer

The filesystem on /dev/sdb1 is not formatted.

Question 2

A system administrator needs to see the boot messages recorded by systemd-journald from the current boot. Which command is most appropriate?

Accepted Answer

journalctl -b. The `journalctl -b` command is the most appropriate because it specifically queries the systemd journal for messages from the current boot. Systemd-journald is the default logging daemon on modern Linux distributions, and `journalctl -b` filters the binary journal to show only entries with a boot ID matching the current boot, which includes kernel messages, service logs, and boot-time events.

Answer

dmesg

Answer

tail -n 50 /var/log/syslog

Answer

cat /var/log/messages

Question 3

Which TWO commands can be used to display information about the CPU(s) in a Linux system? (Choose two.)

Accepted Answer

cat /proc/cpuinfo. Options D and E are both correct. `cat /proc/cpuinfo` reads the virtual file /proc/cpuinfo which the kernel populates with detailed CPU information for each core, such as model name, cache size, and flags. `lscpu` is a utility that collects CPU information from /proc/cpuinfo and sysfs, presenting it in a human-readable tabular format. Both commands are standard on Linux for displaying CPU details.

Answer

uname -m

Answer

lsusb

Answer

cpufreq-info

Question 4

Which TWO conditions would cause the boot process to fall back to the GRUB rescue shell? (Choose two.)

Accepted Answer

The GRUB modules are not loaded from the correct path.. The GRUB rescue shell is entered when the core image cannot locate its modules, typically due to an incorrect module path. This prevents GRUB from loading its normal configuration, causing a fallback to the minimal rescue shell. Missing or corrupt grub.cfg, on the other hand, leads to the GRUB normal shell (grub>), not the rescue shell. Other issues like missing kernel, initramfs, or BIOS failure occur after GRUB or before it starts, so they do not trigger the rescue shell.

Answer

The kernel image is not found in /boot.

Answer

The BIOS cannot find a bootable device.

Answer

The initramfs is missing or corrupt.

Answer

The /boot/grub/grub.cfg file is missing or corrupt.

Question 5

Which THREE of the following are valid runlevels in a traditional SysV init system? (Choose three.)

Accepted Answer

6. In a traditional SysV init system, runlevels are predefined system states numbered from 0 to 6. Runlevel 6 is the standard runlevel for system reboot, where the init process terminates all processes, unmounts filesystems, and restarts the system.

Answer

9

Answer

7

Question 6

Refer to the exhibit. How many physical disks are detected by the kernel, and what are their sizes?

Accepted Answer

Two disks: sda 10.0 GiB, sdb 2.00 GiB. The kernel has detected two physical disks: /dev/sda with a capacity of 10.0 GiB and /dev/sdb with a capacity of 2.00 GiB. This is evident from the output of `fdisk -l`, which lists disk devices and their sizes in gibibytes (GiB), a binary-based unit where 1 GiB = 1024^3 bytes. The kernel enumerates SCSI/SATA disks as /dev/sdX, and the output shows exactly two such devices.

Answer

Two disks: sda 10.7 GB, sdb 2.15 GB

Answer

Three disks: sda, sdb, and an unknown device

Answer

One disk: sda 10.7 GB

Question 7

The system is unable to mount a filesystem that should be identified by UUID 1234-5678. The administrator checks /etc/fstab and finds the entry: UUID=1234-5678 /data ext4 defaults 0 2. What is the most likely cause of the mount failure?

Accepted Answer

The symlink for UUID 1234-5678 is broken.. The most likely cause is that the symbolic link for UUID 1234-5678 is broken. In Linux, UUID-based mounts in /etc/fstab rely on symlinks in /dev/disk/by-uuid/ that point to the actual block device. If the symlink is missing or points to a non-existent device (e.g., after a disk reorder or hardware change), the system cannot resolve the UUID to a device, causing the mount to fail even if the filesystem itself is intact.

Answer

The /data mount point does not exist.

Answer

The device /dev/sda1 is not formatted with ext4.

Answer

The UUID in the fstab entry is incorrect.

Question 8

Refer to the exhibit. What is the current default target?

Accepted Answer

multi-user.target. The current default target is multi-user.target because the output of the `systemctl get-default` command shows 'multi-user.target'. This target provides a non-graphical, multi-user console environment without a display manager, which is the standard default on many server-oriented Linux distributions.

Answer

emergency.target

Answer

rescue.target

Answer

graphical.target

Question 9

A Linux system fails to boot after installing a new kernel. Which step should be taken first to recover the system?

Accepted Answer

Edit GRUB configuration at boot to select the old kernel. When a new kernel fails to boot, the quickest recovery method is to select the previous working kernel from the GRUB boot menu. GRUB typically retains the old kernel entry in its menu (e.g., 'Advanced options for Ubuntu' or a similar submenu), allowing you to boot the system without any external media or reinstallation. This approach avoids the overhead of using a live CD or rescue mode and directly restores functionality.

Answer

Reinstall the original kernel using a live CD

Answer

Boot into single-user mode to fix the kernel

Answer

Use the rescue mode from installation media

Question 10

A system administrator wants to ensure a service named 'app.service' starts automatically on boot in a systemd-based system. Which command should be used?

Accepted Answer

systemctl enable app.service. The correct command is 'systemctl enable app.service' because in systemd-based systems, 'enable' creates the necessary symlinks in the filesystem (typically under /etc/systemd/system/multi-user.target.wants/) to ensure the service starts automatically at boot. In contrast, 'systemctl start' only activates the service immediately without affecting its boot-time behavior.

Answer

systemctl start app.service

Answer

chkconfig app.service on

Answer

update-rc.d app.service enable

Question 11

A server with UEFI firmware and GPT partitioning has a corrupted bootloader. Which command can be used to reinstall GRUB in UEFI mode?

Accepted Answer

grub-install --target=x86_64-efi /dev/sda. `grub-install --target=x86_64-efi /dev/sda` explicitly installs the GRUB EFI bootloader for a 64-bit UEFI system. On a GPT-partitioned disk with UEFI firmware, the bootloader must be installed to the EFI System Partition (ESP) using the appropriate target, and this command ensures the correct EFI binary is placed there.

Answer

grub-mkconfig -o /boot/grub/grub.cfg

Answer

grub2-install /dev/sda

Answer

grub-install /dev/sda

Question 12

Which file is used by GRUB to load the kernel at boot time?

Accepted Answer

/boot/grub/grub.cfg. GRUB (GRand Unified Bootloader) reads its main configuration file, /boot/grub/grub.cfg, to determine which kernel to load and with what parameters. This file contains the menu entries, kernel paths, and initrd directives that GRUB uses at boot time. It is automatically generated by update-grub or grub-mkconfig based on scripts in /etc/grub.d/ and settings in /etc/default/grub.

Answer

/etc/grub.d/

Answer

/etc/default/grub

Answer

/boot/vmlinuz

Question 13

An administrator runs 'lsmod' and sees a module with a usage count of 1. What does this indicate?

Accepted Answer

One process is holding a reference to the module. The usage count in lsmod indicates how many processes or kernel subsystems currently hold a reference to the module. A count of 1 means exactly one process has opened the module (e.g., via a file descriptor or ioctl) or the module is in use by a single kernel component. This is the standard interpretation per the Linux kernel module loader (kmod) and is reflected in the /proc/modules file.

Answer

The module is loaded but not used by any process

Answer

The module is being used by one other module

Answer

The module has one dependency

Question 14

A system takes a long time to boot due to a service that fails to start. Which systemd command can be used to identify the service causing the delay?

Accepted Answer

systemd-analyze blame. The `systemd-analyze blame` command prints a list of all running units, sorted by the time they took to initialize, making it the direct tool to identify which service is causing a boot delay. Unlike other options, it specifically measures and displays the initialization time of each unit, allowing you to pinpoint the slowest service.

Answer

journalctl -u service

Answer

systemctl status

Answer

systemd-analyze critical-chain

Question 15

Which directory contains the kernel modules for the currently running kernel?

Accepted Answer

/lib/modules/$(uname -r). The kernel modules for the currently running kernel are stored in /lib/modules/$(uname -r). The uname -r command returns the exact kernel release version, and the corresponding directory contains all loadable kernel modules (.ko files) compiled for that specific kernel. This is the standard location used by the kernel and tools like modprobe and insmod to locate and load modules.

Answer

/boot

Answer

/etc/modprobe.d

Answer

/usr/src