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CCNA System Architecture Questions

15 of 90 questions · Page 2/2 · System Architecture topic · Answers revealed

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76
Multi-Selecteasy

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

Select 2 answers
A.vmstat
B.du
C.cat /proc/meminfo
D.free
E.top
AnswersC, D

Directly reads kernel memory information.

Why this answer

`/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.

Exam trap

The trap here is that candidates may confuse `du` (disk usage) with memory reporting, or assume `vmstat` or `top` are primary tools for a simple free/used memory display, when `free` and `/proc/meminfo` are the direct and standard answers.

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77
MCQhard

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

A.grub-install --target=x86_64-efi /dev/sda
B.grub-mkconfig -o /boot/grub/grub.cfg
C.grub2-install /dev/sda
D.grub-install /dev/sda
AnswerA

Correct for UEFI systems.

Why this answer

`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.

Exam trap

The trap here is that candidates assume `grub-install /dev/sda` works universally, but without the `--target=x86_64-efi` flag it defaults to BIOS/legacy mode, which fails on UEFI systems with GPT partitioning.

How to eliminate wrong answers

Option B is wrong because `grub-mkconfig -o /boot/grub/grub.cfg` only regenerates the GRUB configuration file; it does not install the bootloader to the disk or ESP, so it cannot fix a corrupted bootloader. Option C is wrong because `grub2-install /dev/sda` (without a target) defaults to legacy BIOS mode, which writes to the Master Boot Record (MBR) and is incompatible with UEFI firmware and GPT partitioning. Option D is wrong because `grub-install /dev/sda` (without `--target=x86_64-efi`) also defaults to BIOS/legacy mode, failing to install the correct EFI binary to the ESP for UEFI boot.

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78
Multi-Selecthard

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

Select 1 answer
A.The GRUB modules are not loaded from the correct path.
B.The kernel image is not found in /boot.
C.The BIOS cannot find a bootable device.
D.The initramfs is missing or corrupt.
E.The /boot/grub/grub.cfg file is missing or corrupt.
AnswersA

Correct. If the modules are not found at the expected path, GRUB cannot proceed beyond the rescue shell.

Why this answer

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.

Exam trap

The trap is that candidates often think a missing grub.cfg leads to the rescue shell, but it actually drops to the normal GRUB shell. The rescue shell is specifically for when GRUB cannot load its own modules.

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79
MCQhard

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

A.3 controllers; SSD at 6.0 Gbps
B.2 controllers; SSD at 6.0 Gbps
C.2 controllers; SSD at 3.0 Gbps
D.1 controller; SSD at 6.0 Gbps
AnswerB

Two ata ports detected; SSD link speed is 6.0 Gbps.

Why this answer

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.

Exam trap

The trap here is that candidates may miscount the number of SATA controllers by confusing individual ports or devices with separate controllers, or misread the speed indicator (e.g., assuming all SATA ports are 3.0 Gbps by default).

How to eliminate wrong answers

Option A is wrong because it claims 3 controllers are detected, but the exhibit only lists two distinct SATA controllers. Option C is wrong because it states the SSD is at 3.0 Gbps, but the exhibit explicitly shows '6 Gbps' for the SSD. Option D is wrong because it says only 1 controller is detected, while the exhibit clearly shows two separate SATA controller entries.

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80
Multi-Selecthard

Which THREE of the following are valid systemd targets?

Select 3 answers
A.rescue.target
B.sysinit.target
C.always.target
D.basic.target
E.runlevel4.target
AnswersA, B, D

A standard systemd target for rescue mode.

Why this answer

A is correct because `rescue.target` is a standard systemd target that provides a minimal single-user environment for system recovery, similar to single-user mode in SysV init. It is a valid target used to boot into a rescue shell with essential services.

Exam trap

The trap here is that candidates may confuse custom or non-existent target names (like `always.target` or `runlevel4.target`) with valid systemd targets, or assume all runlevel numbers have corresponding targets, when in fact systemd only provides targets for runlevels 0-3, 5, and 6.

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81
Multi-Selectmedium

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

Select 2 answers
A.Disable unnecessary systemd services.
B.Use an initramfs with minimal drivers.
C.Replace a hard disk drive with a solid-state drive.
D.Increase the kernel log level to debug.
E.Use ext2 instead of ext4 as the root filesystem.
AnswersA, C

Reduces the number of processes started sequentially.

Why this answer

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.

Exam trap

The trap here is that candidates often confuse 'reducing boot time' with 'reducing kernel size' or 'removing features,' but the two most effective methods are eliminating unnecessary startup processes (services) and upgrading the storage hardware to reduce I/O wait, not tweaking filesystem types or kernel logging verbosity.

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82
MCQhard

A system boots in UEFI mode, and the administrator wants to add a new kernel entry to the EFI boot manager. Which tool should be used?

A.efibootmgr
B.grub2-install
C.lilo
D.mknbi
AnswerA

Efibootmgr is the standard tool to create, delete, and modify EFI boot entries.

Why this answer

In UEFI mode, the system's boot manager is stored in NVRAM, and `efibootmgr` is the standard Linux tool for creating, deleting, and modifying boot entries in the UEFI Boot Manager. It directly manipulates the UEFI Boot Manager variables (e.g., BootOrder, Boot####) via the efivars kernel interface, allowing the administrator to add a new kernel entry without relying on a bootloader like GRUB.

Exam trap

The trap here is that candidates often confuse `grub2-install` (which installs a bootloader) with `efibootmgr` (which manages UEFI boot entries), mistakenly thinking that installing GRUB is the only way to add a kernel entry in UEFI mode.

How to eliminate wrong answers

Option B is wrong because `grub2-install` installs the GRUB2 bootloader to a disk or partition (e.g., the EFI System Partition) and updates the UEFI boot entry for GRUB itself, but it does not add arbitrary kernel entries to the UEFI boot manager; it is a bootloader installation tool, not a boot manager entry editor. Option C is wrong because `lilo` is a legacy bootloader for BIOS/MBR systems and does not support UEFI boot manager manipulation; it is obsolete for UEFI environments. Option D is wrong because `mknbi` is a tool for creating network boot images (e.g., for PXE or Etherboot), not for managing UEFI NVRAM boot entries.

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83
MCQmedium

A system administrator suspects a failing power supply because the server randomly reboots. Which command can be used to check hardware health and event logs?

A.ipmitool sensor list
B.sensors -u
C.lspci -v
D.dmidecode -t baseboard
AnswerA

ipmitool accesses IPMI BMC for sensor readings and event logs, ideal for hardware health monitoring.

Why this answer

The `ipmitool sensor list` command queries the Baseboard Management Controller (BMC) via the IPMI protocol to retrieve real-time sensor readings (e.g., voltages, temperatures, fan speeds) and system event logs (SEL). This is the correct tool for diagnosing hardware-level issues like a failing power supply, as it provides direct access to the server's hardware health monitoring subsystem, independent of the operating system.

Exam trap

The trap here is that candidates confuse `sensors -u` (a user-space tool for reading motherboard sensors via kernel drivers) with IPMI-based hardware monitoring, not realizing that `sensors` cannot access the BMC or event logs, and thus cannot diagnose random reboots caused by power supply issues.

How to eliminate wrong answers

Option B is wrong because `sensors -u` reads from kernel-based sensor drivers (e.g., lm-sensors) and only reports current sensor values in a raw format; it does not access the BMC or event logs, and it cannot detect power supply failures that cause random reboots if the OS is already unstable. Option C is wrong because `lspci -v` lists PCI devices and their configuration details, but it does not monitor hardware health, sensor data, or event logs; it is purely for enumerating the PCI bus. Option D is wrong because `dmidecode -t baseboard` decodes DMI/SMBIOS tables to show motherboard information (e.g., manufacturer, serial number), but it provides no dynamic sensor readings or event log history; it is static hardware inventory data, not a health monitoring tool.

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84
Multi-Selecteasy

Which TWO of the following are valid methods to list currently loaded kernel modules?

Select 2 answers
A.dmesg | grep module
B.lsmod
C.modprobe -l
D.cat /proc/modules
E.modinfo
AnswersB, D

Standard command to list loaded modules.

Why this answer

B (lsmod) is correct because it reads the /proc/modules file and formats the output in a human-readable table, listing all currently loaded kernel modules. D (cat /proc/modules) is also correct because /proc/modules is the kernel interface that directly exposes the list of loaded modules with their size, usage count, and dependent modules.

Exam trap

The trap here is that candidates confuse commands that list available modules (like modprobe -l or find /lib/modules) with commands that list currently loaded modules, or they assume dmesg is a valid module listing tool because it shows kernel messages related to module loading.

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85
MCQhard

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?

A.Create separate LVM logical volumes on each disk and mount them at different mount points.
B.Configure RAID 0 across both disks to combine speed.
C.Use symbolic links to redirect file access to the SSD.
D.Use a union mount to overlay the SSD on top of the HDD.
AnswerA

LVM allows flexible allocation of storage from different physical volumes.

Why this answer

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.

Exam trap

The trap here is that candidates may confuse RAID 0's speed benefits with the goal of isolating hot data, failing to recognize that RAID 0 mixes all data across both disks, preventing the administrator from selectively placing frequently accessed files on the faster SSD.

How to eliminate wrong answers

Option B is wrong because RAID 0 stripes data across both disks, combining their storage capacity and speed but also mixing frequently and infrequently accessed data on both the SSD and HDD, which negates the goal of isolating hot data on the faster SSD. Option C is wrong because symbolic links redirect file access at the filesystem level but do not provide a mechanism to automatically or efficiently place frequently accessed files on the SSD; they require manual management and do not leverage any filesystem feature for performance tiering. Option D is wrong because a union mount overlays one filesystem on top of another, but it does not intelligently direct frequently accessed files to the SSD; it simply merges directories, and writes typically go to the top layer, which could be the HDD, defeating the purpose.

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86
MCQeasy

Which command displays the system's architecture (e.g., x86_64)?

A.lscpu
B.All of the above
C.arch
D.uname -m
AnswerB

All three commands can display the system architecture.

Why this answer

('All of the above') is correct because each of the listed commands—lscpu, arch, and uname -m—can display the system's architecture (e.g., x86_64). lscpu parses /proc/cpuinfo to show architecture details, arch prints the machine hardware name directly, and uname -m outputs the kernel's machine hardware name, all of which report the same architecture identifier on a given system.

Exam trap

The trap here is that candidates often assume only one command can display architecture, overlooking that multiple commands (lscpu, arch, uname -m) all serve this purpose, making 'All of the above' the correct answer when it is listed.

How to eliminate wrong answers

Option A is wrong because lscpu is a valid command that displays architecture information, but it is not the only one; the question asks which command displays the architecture, and since multiple commands do, 'All of the above' is the correct choice. Option C is wrong because arch is a valid command that outputs the architecture, but again it is not the only one, making 'All of the above' the comprehensive answer. Option D is wrong because uname -m is a valid command that shows the machine hardware name (architecture), but it is not the only command that does so, so the correct answer is the inclusive option.

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87
MCQmedium

A data center server with two NICs (eth0 and eth1) is configured for network bonding in mode 1 (active-backup). The admin notices that after a cable pull on eth0, the bond interface fails over to eth1 as expected. However, when the cable is reconnected to eth0, the bond remains on eth1 indefinitely. The admin checks /proc/net/bonding/bond0 and sees that eth0 is marked as 'up' but not as 'active'. Which parameter is most likely missing from the bond configuration? Options: A) 'miimon=100' to enable link monitoring, B) 'downdelay=0', C) 'updelay=0', D) 'primary=eth0' to prefer eth0 as the active slave.

A.updelay=0
B.downdelay=0
C.miimon=100
D.primary=eth0
AnswerD

Designates eth0 as preferred; the bond will switch back when it becomes available.

Why this answer

The bond is in active-backup mode (mode 1) and eth0 is marked as 'up' but not 'active' after reconnection. Without the 'primary=eth0' parameter, the bond does not automatically switch back to the preferred slave (eth0) once it becomes available; it only fails over to eth1 when eth0 goes down. Setting 'primary=eth0' ensures that eth0 is always preferred as the active slave when it is in 'up' state, triggering a failback.

Exam trap

The trap here is that candidates assume 'miimon' alone handles both failover and failback, but in active-backup mode, failback to a preferred slave requires the explicit 'primary' parameter.

How to eliminate wrong answers

Option A is wrong because 'miimon=100' enables link monitoring via MII, which is already functioning (the bond detected the cable pull and failed over), so it is not the missing parameter. Option B is wrong because 'downdelay=0' (default) controls the delay before deactivating a slave after link loss; the issue is about failback, not failover timing. Option C is wrong because 'updelay=0' (default) controls the delay before considering a link as up after reconnection; the bond already sees eth0 as 'up', so the problem is not a delay but the lack of a preference to switch back.

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88
MCQmedium

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?

A.systemctl start app.service
B.systemctl enable app.service
C.chkconfig app.service on
D.update-rc.d app.service enable
AnswerB

Enables the service to start at boot.

Why this answer

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.

Exam trap

The trap here is that candidates confuse 'start' (immediate activation) with 'enable' (boot-time activation), or mistakenly apply legacy SysV commands like 'chkconfig' or 'update-rc.d' to a systemd environment, which is a common pitfall in LPIC-1 exams.

How to eliminate wrong answers

Option A is wrong because 'systemctl start app.service' only starts the service immediately in the current session, but does not configure it to start automatically on boot. Option C is wrong because 'chkconfig' is a legacy tool for SysV init systems (e.g., RHEL/CentOS 6 and earlier), not for systemd-based systems; it would not work or would be deprecated. Option D is wrong because 'update-rc.d' is a Debian/Ubuntu-specific command for managing SysV init scripts, not for systemd services; it would not properly enable a systemd unit.

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89
MCQeasy

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

A.emergency.target
B.multi-user.target
C.rescue.target
D.graphical.target
AnswerB

Both the command output and the symlink indicate multi-user.target.

Why this answer

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.

Exam trap

In LPI exams, candidates often confuse rescue.target (single-user with basic services) with multi-user.target (full multi-user console) or assume graphical.target is the default on all systems.

How to eliminate wrong answers

Option A is wrong because emergency.target is a minimal environment used for troubleshooting when the system cannot boot normally; it is not the default target shown in the exhibit. Option C is wrong because rescue.target is a single-user mode with basic system services, but it is not the default target displayed. Option D is wrong because graphical.target is the default for desktop-oriented installations that include a display manager, but the exhibit explicitly shows multi-user.target as the current default.

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90
MCQmedium

A system administrator notices that the system boots to the graphical interface but wants to change it to boot to a non-graphical multi-user target. Which command will make this change persistent?

A.systemctl set-default multi-user.target
B.systemctl isolate multi-user.target
C.systemctl enable multi-user.target
D.systemctl start multi-user.target
AnswerA

Sets the default target persistently.

Why this answer

`systemctl set-default multi-user.target` changes the default systemd target to `multi-user.target`, which boots to a non-graphical multi-user environment. This change is persistent across reboots, as it updates the symlink `/etc/systemd/system/default.target` to point to `multi-user.target`.

Exam trap

The trap here is that candidates confuse `isolate` (which changes the current target but is not persistent) with `set-default` (which makes the change permanent), leading them to incorrectly select Option B.

How to eliminate wrong answers

Option B is wrong because `systemctl isolate multi-user.target` immediately switches the current running target to `multi-user.target`, but this change is not persistent; it only affects the current session and does not modify the default target for future boots. Option C is wrong because `systemctl enable multi-user.target` is not a valid systemd command for setting the default target; `enable` is used to enable services or units at boot, not to set the default target. Option D is wrong because `systemctl start multi-user.target` starts the target immediately but does not make it the default for subsequent boots; it only activates the target in the current session.

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