LPIC-1 Devices, Filesystems and FHS — Timed 20 Questions

Question 1

Which THREE directories are required to be directly under the root filesystem (/) according to the Filesystem Hierarchy Standard? (Choose exactly three.)

Accepted Answer

/var. According to the Filesystem Hierarchy Standard (FHS), the directories /bin, /sbin, and /var are required to be directly under the root filesystem. /bin contains essential user command binaries, /sbin contains system administration binaries, and /var contains variable data such as logs and databases. While /lib is also required, the question asks for exactly three options, and among the given choices, these three are the only ones that are both required and part of the set that must be directly under /.

Answer

/lib

Answer

/home

Question 2

Which TWO of the following are valid methods to specify a partition in /etc/fstab?

Accepted Answer

UUID. UUID and LABEL are both valid identifiers for partitions in /etc/fstab. UUID uses the filesystem's universally unique identifier, while LABEL uses a human-readable name assigned to the filesystem. Both are persistent across reboots and preferred over device names like /dev/sda1, which can change.

Answer

PARTUUID

Answer

DEVPATH

Answer

ID

Question 3

According to the Filesystem Hierarchy Standard (FHS), in which directory should third-party static libraries be installed?

Accepted Answer

/usr/local/lib. According to the Filesystem Hierarchy Standard (FHS), third-party static libraries should be installed in directories dedicated to locally-installed software. /usr/local/lib is for libraries that support site-specific software managed by the local administrator. /opt/lib is for libraries that are part of add-on application packages (such as those in /opt). These directories are intended for third-party static libraries that are not part of the core operating system's package management. /usr/lib (D) is reserved for libraries from the distribution's package manager, and /lib (A) is for libraries required for booting and core system functionality.

Answer

/lib

Answer

/usr/lib

Question 4

A system administrator wants to mount a USB flash drive formatted with the ext4 filesystem. The device is detected as /dev/sdc1. Which command should be used to mount the device to /mnt/usb?

Accepted Answer

mount /dev/sdc1 /mnt/usb. The standard mount syntax is `mount [options] `. For ext4 filesystems, the kernel auto-detects the type, so the `-t ext4` option is unnecessary. While option D is syntactically valid, it is considered incorrect here because it includes an extraneous `-t ext4` flag; the question expects the simplest and most straightforward command. Option A is incorrect because `-a` mounts all filesystems listed in /etc/fstab, not a specific device. Option B is incorrect because the arguments are reversed (device must come before the mount point). Therefore, the command that correctly mounts /dev/sdc1 to /mnt/usb is `mount /dev/sdc1 /mnt/usb`.

Answer

mount -a /dev/sdc1 /mnt/usb

Answer

mount /mnt/usb /dev/sdc1

Answer

mount -t ext4 /dev/sdc1 /mnt/usb

Question 5

A Linux system has two SATA disks: /dev/sda (250GB) and /dev/sdb (500GB). The administrator wants to create a logical volume group named 'vgdata' using partitions on both disks, then create a 600GB logical volume named 'lvdata' for a database. Which sequence of commands should be used?

Accepted Answer

pvcreate /dev/sda1 /dev/sdb1; vgcreate vgdata /dev/sda1 /dev/sdb1; lvcreate -L 600G -n lvdata vgdata. It follows the proper LVM sequence: first create physical volumes (PVs) on partitions /dev/sda1 and /dev/sdb1 (the partitions on the two disks given in the scenario), then create the volume group 'vgdata' from those PVs using vgcreate, and finally create the logical volume 'lvdata' with a size of 600GB using lvcreate. This order ensures that the PVs exist before the VG is created, and the VG exists before the LV is created. Only option C uses the correct device names that match the system's disks (/dev/sda and /dev/sdb).

Answer

pvcreate /dev/sdb1 /dev/sdc1; lvcreate -L 600G -n lvdata vgdata; vgcreate vgdata /dev/sdb1 /dev/sdc1

Answer

pvcreate /dev/sdb /dev/sdc; vgcreate vgdata /dev/sdb /dev/sdc; lvcreate -L 600G -n lvdata vgdata

Answer

vgcreate vgdata /dev/sdb1 /dev/sdc1; pvcreate /dev/sdb1 /dev/sdc1; lvcreate -L 600G -n lvdata vgdata

Question 6

During boot, a Linux system displays 'Kernel panic – not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which of the following is the most likely cause?

Accepted Answer

The kernel lacks the necessary driver for the storage controller.. The error 'unknown-block(0,0)' indicates the kernel cannot find a device to mount as root. This typically occurs when the kernel lacks the driver for the storage controller (e.g., SATA, NVMe, SCSI host adapter) needed to access the root filesystem. Without the driver, the kernel cannot enumerate the block device, even if the root= parameter is correct and the filesystem is intact.

Answer

The root filesystem is corrupted and needs fsck.

Answer

The root= parameter in the boot loader points to a non-existent device.

Answer

The initrd is missing or corrupted.

Question 7

Which of the following commands displays the amount of free disk space on all mounted filesystems in a human-readable format?

Accepted Answer

df -h. The `df -h` command displays disk space usage for all mounted filesystems with sizes in human-readable units (e.g., KB, MB, GB). The `-h` flag converts raw block counts into powers of 1024 with appropriate suffixes, making the output easy to interpret at a glance.

Answer

df -i

Answer

du -sh

Answer

df -T

Question 8

An administrator needs to create a new ext4 filesystem on /dev/sdb1 and wants to reserve 2% of the blocks for the root user. Which command should be used?

Accepted Answer

mkfs.ext4 -m 2 /dev/sdb1. The `-m` flag in `mkfs.ext4` specifies the percentage of filesystem blocks reserved for the root user (superuser). By default, ext4 reserves 5% of blocks; using `-m 2` reduces this to 2%, as required. This command creates a new ext4 filesystem on `/dev/sdb1` with the specified reserved block percentage.

Answer

tune2fs -m 2 /dev/sdb1

Answer

mke2fs -r 2 /dev/sdb1

Answer

mkfs.ext4 -R 2 /dev/sdb1

Question 9

A Linux system has a software RAID1 array /dev/md0 consisting of /dev/sda1 and /dev/sdb1. After replacing a failed disk, the administrator runs 'mdadm --manage /dev/md0 --add /dev/sdc1', but the array remains degraded. Which command should be used to check the status of the array?

Accepted Answer

mdadm --detail /dev/md0. The `mdadm --detail /dev/md0` command displays the current state of the RAID array, including its status (e.g., degraded, active), the number of active and failed devices, and the sync/resync progress. Since the array remains degraded after adding a new disk, this command will show whether the new disk has been properly integrated or if there is an underlying issue, such as a missing or failed component.

Answer

mdadm --examine /dev/sdc1

Answer

mdadm --version

Answer

mdadm --query /dev/md0

Question 10

Which directory in the Filesystem Hierarchy Standard (FHS) contains essential user command binaries that are needed in single-user mode?

Accepted Answer

/bin. The /bin directory contains essential user command binaries (e.g., ls, cp, mv) that are required for system booting and repair in single-user mode. According to the FHS, /bin is intended for commands needed by both the system administrator and users when no other filesystems are mounted, making it critical for single-user mode operations.

Answer

/tmp

Answer

/sbin

Answer

/boot

Question 11

An administrator needs to mount an ISO image file /tmp/image.iso to the directory /mnt/iso. Which command should be used?

Accepted Answer

mount -o loop /tmp/image.iso /mnt/iso. The `-o loop` option tells the mount command to use a loop device, which is required to mount a file (like an ISO image) as if it were a block device. Without the loop option, mount expects a block device path, not a regular file.

Answer

mount -o ro /tmp/image.iso /mnt/iso

Answer

mount -t iso /tmp/image.iso /mnt/iso

Answer

mount /tmp/image.iso /mnt/iso

Question 12

A system is running out of disk space on /var. The administrator finds that /var/log/syslog is 4GB. Which of the following is the best course of action to prevent future issues while keeping recent logs?

Accepted Answer

Configure logrotate to rotate and compress logs daily.. Logrotate is the standard Linux utility for managing log file growth. By configuring it to rotate and compress logs daily, the administrator can automatically archive old logs (e.g., /var/log/syslog.1.gz) and keep only recent entries in the active file, preventing disk space exhaustion without losing historical data.

Answer

Use 'truncate -s 0 /var/log/syslog' to empty the file.

Answer

Configure syslog to stop logging.

Answer

Delete /var/log/syslog and create an empty file.

Question 13

Which TWO of the following are valid mount options for the ext4 filesystem?

Accepted Answer

data=journal. 'data=journal' is a valid mount option for ext4 that enables journaling of both metadata and file data, providing the highest level of data integrity by writing all data to the journal before the main filesystem. Option C is correct because 'noatime' is a standard mount option that disables updating the access time (atime) on inodes, reducing disk writes and improving performance.

Answer

sync

Answer

ro

Answer

noload

Question 14

Which THREE of the following commands can be used to display information about block devices?

Accepted Answer

lsblk. A is correct because `lsblk` lists all block devices (e.g., hard drives, SSDs, partitions) by reading the sysfs filesystem and the udev database, displaying their names, sizes, and mount points. It is the primary command for viewing block device topology.

Answer

free

Answer

ip link

Question 15

Which TWO of the following are true about the /proc filesystem?

Accepted Answer

It is a pseudo-filesystem that contains runtime system information.. The /proc filesystem is a pseudo-filesystem that does not exist on disk; it is created by the kernel at runtime to expose system and process information (e.g., /proc/cpuinfo, /proc/meminfo). It provides a mechanism for user-space programs to query kernel data structures without making system calls directly.

Answer

It is formatted with the ext4 filesystem.

Answer

It is a network filesystem.

Answer

It is used to store persistent configuration data.

Question 16

Based on the lsblk output, which of the following is true?

Accepted Answer

The partition /dev/sda2 is an extended partition.. In the lsblk output, /dev/sda2 is listed as a partition of type 'Extended' (typically shown as 'Extended' or with a partition type ID of 5 in fdisk). Extended partitions cannot be directly formatted or mounted; they serve as containers for logical partitions (e.g., sda5). The lsblk output would show sda2 with no filesystem or mount point, and sda5 would appear as a child of sda2, confirming sda2 is extended.

Answer

The disk /dev/sdb has an extended partition.

Answer

The root filesystem is mounted from /dev/sda5.

Answer

The disk /dev/sda has a primary partition sda5.

Question 17

Based on the /etc/fstab entry, which filesystem will be checked by fsck at boot time?

Accepted Answer

/ and /boot only. The /etc/fstab entry shows that only the root filesystem (/) and /boot have a non-zero value in the pass field (the sixth field). The fsck command at boot time checks filesystems with a pass number greater than 0, and the order is determined by the pass number (root typically 1, /boot 2). Since /mnt/data and swap have a pass value of 0, they are skipped.

Answer

All filesystems except NFS

Answer

/, /boot, and /mnt/data

Answer

/, /boot, and swap

Question 18

A company runs a web server on Linux with two hard disks: /dev/sda (500GB) and /dev/sdb (500GB). The root filesystem is on /dev/sda1, and /var is on /dev/sda2. The administrator wants to add a new disk /dev/sdc (500GB) to be used as additional storage for /var/www/html. The new disk should be configured as an LVM physical volume and added to an existing volume group named 'vg_web'. The volume group currently has 200GB free space from /dev/sdb1. The administrator intends to extend the logical volume 'lv_web' mounted at /var/www/html by 300GB. Which of the following is the correct sequence of commands to achieve this without data loss?

Accepted Answer

pvcreate /dev/sdc1; vgextend vg_web /dev/sdc1; lvextend --resizefs -L +300G /dev/vg_web/lv_web. Both options C and D are correct for extending an ext4 filesystem. Option C uses the `--resizefs` flag with `lvextend`, which automatically resizes the filesystem after extending the logical volume. This flag is supported in modern LVM2 for ext4 and other filesystems. Option D performs the resize explicitly with `resize2fs`. Both achieve the same result. Option A omits the filesystem resize, so the new space is not usable. Option B uses the whole disk without a partition, which is not standard practice and may cause issues. Therefore, the correct sequence includes either the `--resizefs` flag or an explicit resize step.

Answer

pvcreate /dev/sdc1; vgextend vg_web /dev/sdc1; lvextend -L +300G /dev/vg_web/lv_web

Answer

pvcreate /dev/sdc; vgextend vg_web /dev/sdc; lvextend -L +300G /dev/vg_web/lv_web; resize2fs /dev/vg_web/lv_web

Question 19

A Linux administrator is troubleshooting a server that fails to boot with the error 'Give root password for maintenance (or press Control-D to continue)'. The root filesystem is on /dev/sda2, formatted as ext4. The administrator suspects a filesystem inconsistency. The server is in a remote data center and the administrator has console access via IPMI. Which of the following is the safest procedure to repair the filesystem?

Accepted Answer

At the maintenance prompt, run 'mount -o remount,ro /dev/sda2 /' then 'fsck -f /dev/sda2' and then 'reboot'.. It first remounts the root filesystem as read-only to prevent any writes during the repair, which is essential for a consistent fsck run on an ext4 filesystem. Then it uses 'fsck -f' to force a check even if the filesystem appears clean, followed by a reboot to exit maintenance mode. This is the safest procedure as it avoids the risk of the filesystem being mounted read-write during repair, which could cause further corruption.

Answer

At the maintenance prompt, run 'fsck /dev/sda2' and answer yes to all prompts.

Answer

At the maintenance prompt, run 'fsck -y /dev/sda2' to force repair.

Answer

At the maintenance prompt, run 'fsck -a /dev/sda2' to automatically repair.

Question 20

A system administrator notices that the /tmp directory is filling up quickly, causing applications to fail. The administrator wants to ensure that files in /tmp are automatically cleaned after a certain period. Which of the following is the best approach without installing additional software?

Accepted Answer

Configure the systemd-tmpfiles service with a configuration file to clean /tmp regularly.. Systemd-based Linux distributions include the systemd-tmpfiles service, which can be configured via files in /etc/tmpfiles.d/ to automatically clean temporary files based on age, size, or other criteria. This approach uses built-in systemd functionality without requiring additional software, and it is the recommended method for managing /tmp cleanup on modern systems.

Answer

Add a cron job that runs 'rm -rf /tmp/*' every hour.

Answer

Install tmpwatch and configure it to clean files older than 1 day.

Answer

Set the sticky bit on /tmp to automatically delete old files.