LPIC-1 System Architecture — Timed 50 Questions

Question 1

Which command shows the amount of free and used memory in the system, including swap?

Accepted Answer

free -h. The `free -h` command displays the total, used, and free physical memory (RAM) and swap space in a human-readable format (e.g., GiB, MiB). The `-h` flag ensures output is scaled to appropriate units, making it the direct and correct tool for checking both memory and swap usage.

Answer

top

Answer

df -h

Answer

vmstat

Question 2

A system administrator needs to blacklist the kernel module 'pcspkr' to disable the PC speaker. Which is the correct method?

Accepted Answer

Add 'blacklist pcspkr' to /etc/modprobe.d/blacklist.conf. The 'blacklist' directive in a file under /etc/modprobe.d/ tells modprobe to ignore the specified module entirely, preventing it from being loaded automatically or manually. This is the standard method to permanently disable a kernel module like 'pcspkr' without removing its files.

Answer

Add 'load pcspkr' to /etc/modules

Answer

Add 'install pcspkr /bin/true' to /etc/modprobe.d/blacklist.conf

Answer

Remove the module from /lib/modules/$(uname -r)/kernel/drivers

Question 3

A system administrator notices that the server's clock is consistently off by several minutes. Which service should be used to synchronize the time with an external time source?

Accepted Answer

ntpd. The Network Time Protocol (NTP) daemon (ntpd) is the traditional and widely used service for synchronizing a server's clock with an external time source. It continuously adjusts the system time by communicating with NTP servers, compensating for clock drift and network delays to maintain accurate time. This makes ntpd the correct choice for resolving a consistent clock offset of several minutes.

Answer

timed

Answer

chronyd

Answer

systemd-timesyncd

Question 4

During boot, the kernel must mount the root filesystem. Which of the following is responsible for providing the kernel with the location of the root filesystem?

Accepted Answer

boot loader. The boot loader (e.g., GRUB) is responsible for loading the kernel into memory and passing it the location of the root filesystem via kernel command-line parameters such as `root=`. Without this parameter, the kernel would not know which block device or partition to mount as `/`. The boot loader reads configuration files (e.g., `grub.cfg`) that specify this parameter, making it the direct provider of the root filesystem location.

Answer

udev

Answer

initramfs

Answer

init

Question 5

A server has two disk drives: /dev/sda (SSD) and /dev/sdb (HDD). The administrator wants to place frequently accessed files on the SSD for performance. Which approach best achieves this using Linux filesystem features?

Accepted Answer

Create separate LVM logical volumes on each disk and mount them at different mount points.. LVM allows the administrator to create separate logical volumes on each physical disk (/dev/sda and /dev/sdb) and mount them at distinct mount points. By placing frequently accessed files on the SSD logical volume and less critical data on the HDD logical volume, the administrator can directly control which files benefit from the SSD's faster performance without mixing data or requiring complex overlays.

Answer

Configure RAID 0 across both disks to combine speed.

Answer

Use symbolic links to redirect file access to the SSD.

Answer

Use a union mount to overlay the SSD on top of the HDD.

Question 6

A technician is troubleshooting a system that fails to boot with the error 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. What is the most likely cause?

Accepted Answer

The kernel lacks the necessary driver for the storage controller.. The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates that the kernel cannot locate or access the root filesystem. This typically occurs because the kernel lacks the necessary driver (module) for the storage controller (e.g., SATA, SCSI, NVMe) that the root device is connected to, so it cannot read the partition table or mount the root filesystem.

Answer

The init binary is missing or corrupted.

Answer

The root filesystem is corrupted and needs fsck.

Answer

The boot loader is not installed correctly.

Question 7

Which hardware component uses a unique address to identify itself on the network at the data link layer?

Accepted Answer

MAC address. The MAC address (Media Access Control) is a unique 48-bit identifier burned into the network interface controller (NIC) by the manufacturer. It operates at Layer 2 (data link layer) of the OSI model, enabling devices on the same local network segment to communicate directly using protocols like Ethernet or Wi-Fi.

Answer

IP address

Answer

Hostname

Answer

Port number

Question 8

A Linux system has two network interfaces: eth0 and eth1. The administrator wants to bond them for increased throughput. Which kernel module is required for bonding?

Accepted Answer

bonding. The bonding driver in Linux allows multiple network interfaces to be aggregated into a single logical interface for increased throughput or redundancy. The correct kernel module is named 'bonding' (loaded via modprobe bonding or compiled into the kernel), which implements the IEEE 802.3ad Link Aggregation standard and other bonding modes. Option B is correct because 'bonding' is the exact module name used in the Linux kernel.

Answer

aggregation

Answer

team

Answer

bond

Question 9

An administrator needs to ensure that a specific kernel module is loaded automatically at boot. Which file should be used to permanently load the module?

Accepted Answer

/etc/modules. On modern Linux systems using a standard init system, the file /etc/modules (or /etc/modules-load.d/*.conf on systemd-based distributions) is read at boot to load specified kernel modules automatically. This file lists module names one per line, and the kernel's module loading mechanism processes it early in the boot sequence to ensure the module is available before services that depend on it start.

Answer

/etc/modprobe.d/modules.conf

Answer

/etc/sysconfig/modules

Answer

/etc/conf.modules

Question 10

Which command displays information about the CPU, including model name, cache size, and flags?

Accepted Answer

lscpu. The `lscpu` command is the correct choice because it is specifically designed to display CPU architecture information, including model name, cache sizes, and flags (such as SSE, AES, etc.), by reading data from sysfs and /proc/cpuinfo in a human-readable format. It provides a concise summary without requiring root privileges, making it the most appropriate tool for this task.

Answer

uname -a

Answer

cat /proc/cpuinfo

Answer

dmidecode

Question 11

A server with a udev rule fails to consistently assign a persistent network interface name. What is the most likely cause?

Accepted Answer

The network interface's MAC address is not unique or changes.. Persistent network interface names in Linux rely on udev rules that match attributes like MAC address. If the MAC address is not unique (e.g., due to a virtual machine or cloned NIC) or changes (e.g., after hardware replacement or driver update), the rule will fail to consistently identify the interface, causing the name assignment to be unpredictable.

Answer

The rule uses an incorrect operator.

Answer

The BIOS device name is configured incorrectly.

Answer

The kernel module for the NIC is not loaded.

Question 12

Which TWO of the following are valid methods to reduce boot time on a Linux system? (Select exactly 2.)

Accepted Answer

Disable unnecessary systemd services.. Disabling unnecessary systemd services reduces the number of processes that must be started during boot, directly decreasing the time spent in the target phase of systemd's parallel service activation. Each disabled service eliminates its own dependency resolution, unit loading, and execution overhead, which is especially impactful on systems with many enabled services.

Answer

Use an initramfs with minimal drivers.

Answer

Increase the kernel log level to debug.

Answer

Use ext2 instead of ext4 as the root filesystem.

Question 13

Which THREE of the following are characteristics of UEFI firmware compared to legacy BIOS? (Select exactly 3.)

Accepted Answer

Supports booting from disks larger than 2 TB.. UEFI firmware uses the GUID Partition Table (GPT) instead of MBR, which supports 64-bit logical block addressing (LBA). This allows addressing disks larger than 2 TB, as the MBR scheme is limited to 32-bit LBA and a maximum addressable size of approximately 2.2 TB. Therefore, option A is correct.

Answer

Uses the Master Boot Record partition table.

Answer

Requires a boot loader stored in the Master Boot Record.

Question 14

Which TWO commands can be used to display the amount of free and used memory on a Linux system? (Select exactly 2.)

Accepted Answer

cat /proc/meminfo. `/proc/meminfo` is a virtual file maintained by the kernel that provides detailed, real-time memory statistics, including total, free, available, and used memory. Reading this file with `cat` directly displays the current memory usage without any additional processing.

Answer

vmstat

Answer

du

Answer

top

Question 15

Refer to the exhibit. The system has a single disk with three partitions. Which partition contains the root filesystem?

Accepted Answer

sda3. The root filesystem is mounted from the partition that contains the / (root) directory. In Linux, partitions are numbered starting from 1 (e.g., sda1, sda2, sda3). The device sda itself refers to the entire disk, not a partition. Since the system has three partitions and the correct answer is sda3, partition sda3 must be the one designated as the root filesystem, typically identified by the mount point '/' in /etc/fstab or by the kernel boot parameter root=.

Answer

sda

Answer

sda1

Answer

sda2

Question 16

Refer to the exhibit. How many SATA controllers are detected, and what is the connection speed of the SSD?

Accepted Answer

2 controllers; SSD at 6.0 Gbps. The output from `lspci` shows two SATA controllers: one identified as 'SATA controller: Intel Corporation 82801IBM/IEM (ICH9M/ICH9M-E) 4 port SATA Controller' and another as 'SATA controller: Intel Corporation 82801IBM/IEM (ICH9M/ICH9M-E) 2 port SATA Controller'. The SSD is connected to the 6 Gbps port, as indicated by the '6 Gbps' label in the device listing, confirming a 6.0 Gbps connection speed.

Answer

3 controllers; SSD at 6.0 Gbps

Answer

2 controllers; SSD at 3.0 Gbps

Answer

1 controller; SSD at 6.0 Gbps

Question 17

A company runs a critical database server on Linux. The server has a hardware RAID controller with two logical volumes: one for the operating system (LV1) and one for the database data (LV2). The server uses LVM on top of the RAID volumes. Recently, the database performance has degraded. The administrator suspects that the file system on LV2 is heavily fragmented. The server uses the ext4 filesystem. The administrator wants to check the fragmentation level and, if necessary, defragment the filesystem without unmounting it or causing downtime. What should the administrator do to minimize fragmentation impact while maintaining availability?

Accepted Answer

Use the e4defrag command with the -v option on the mount point to check and defragment files online.. e4defrag is a userspace tool that provides online defragmentation for ext4 filesystems. It can check fragmentation levels and defragment files without unmounting the filesystem, thus avoiding downtime. This allows the administrator to minimize fragmentation impact while maintaining availability.

Answer

Create a new filesystem on LV2, copy data back, and symlink the old mount point to the new one.

Answer

Use tune2fs to set the reserved block percentage to 0 and increase the inode size.

Answer

Schedule a maintenance window, unmount LV2, run e2fsck -fn, then run e2fsck -D to defragment.

Question 18

A Linux system administrator is tasked with setting up a new server that will host multiple virtual machines using KVM. The server has 64 GB of RAM and two physical CPUs, each with 8 cores (16 threads). The administrator needs to allocate resources efficiently. The VMs will have varying workloads. The administrator wants to ensure that the host system has enough resources for itself and that VMs can use all available CPU cores. Which approach should the administrator take to configure CPU allocation for the host and VMs?

Accepted Answer

Use CPU pinning to reserve two physical cores for the host and distribute the remaining cores among VMs using host-passthrough mode.. It reserves two physical cores for the host system to ensure its stability and performance, while distributing the remaining cores among VMs using CPU pinning and host-passthrough mode. This approach allows VMs to access the full CPU feature set and all available cores efficiently, balancing host overhead with VM resource needs in a KVM environment.

Answer

Use QEMU emulation instead of KVM to reduce CPU overhead.

Answer

Pin all physical CPU cores to the VMs using virsh vcpupin, and leave no cores for the host.

Answer

Overcommit CPU resources by assigning 32 vCPUs to each VM, relying on the hypervisor to schedule.

Question 19

A system administrator notices that a server with a freshly installed Linux system fails to boot with the error 'No bootable device found'. The server has a single SATA hard disk connected to the motherboard's SATA controller. Which of the following is the most likely cause of this issue?

Accepted Answer

The BIOS boot order is set to a device that does not contain a bootable operating system.. The error 'No bootable device found' occurs during the BIOS/UEFI POST phase, before any bootloader is loaded. This indicates that the system firmware cannot find a valid boot sector on any device in its boot order. Since the server has a single SATA hard disk, the most likely cause is that the BIOS boot order is set to a different device (e.g., a network boot or removable media) that does not contain a bootable operating system, or the hard disk itself is not listed first in the boot priority.

Answer

The root filesystem is formatted with an unsupported filesystem type.

Answer

The kernel module for the SATA controller is not included in the initramfs.

Answer

The GRUB bootloader configuration file is missing or corrupted.

Question 20

Which TWO of the following are valid methods to change the default runlevel on a SysV init-based system?

Accepted Answer

Edit /etc/inittab to set the initdefault line.. In SysV init-based systems, the default runlevel is defined in the /etc/inittab file by the 'initdefault' line, which specifies the runlevel the system should enter after boot. Editing this line is the standard method to permanently change the default runlevel. Option B correctly identifies this mechanism.

Answer

Use the 'runlevel' command to set the default runlevel.

Answer

Use 'systemctl set-default' to set the default runlevel.

Answer

Use the 'telinit' command to change the default runlevel.