LPIC-1 Devices, Filesystems and FHS — 30 Questions

Question 1

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. Option C is correct because the standard syntax for the mount command is `mount [options] `. Here, `/dev/sdc1` is the device and `/mnt/usb` is the target directory. The ext4 filesystem is auto-detected by the kernel, so specifying `-t ext4` is optional but not incorrect.

Answer

mount -a /dev/sdc1 /mnt/usb

Answer

mount /mnt/usb /dev/sdc1

Answer

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

Question 2

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/sdb1 /dev/sdc1; vgcreate vgdata /dev/sdb1 /dev/sdc1; lvcreate -L 600G -n lvdata vgdata. Option C is correct because it follows the proper LVM sequence: first create physical volumes (PVs) on the partitions /dev/sdb1 and /dev/sdc1 using pvcreate, 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.

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 3

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 4

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 5

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. Option A is correct because 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 6

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 7

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 8

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. Option A is correct because 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 9

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.. Option B is correct because 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 10

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

Accepted Answer

data=journal. Option B is correct because '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 11

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 12

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

Accepted Answer

It is a pseudo-filesystem that contains runtime system information.. Option C is correct because 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 13

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

Accepted Answer

The partition /dev/sda2 is an extended partition.. Option C is correct because 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 14

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 dump field (the fifth field). The fsck command at boot time checks filesystems with a dump value greater than 0, in the order specified by the pass number (the sixth field). Since /mnt/data and swap have a dump value of 0, they are skipped.

Answer

All filesystems except NFS

Answer

/, /boot, and /mnt/data

Answer

/, /boot, and swap

Question 15

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 -L +300G /dev/vg_web/lv_web; resize2fs /dev/vg_web/lv_web. Option D is correct because it follows the proper sequence: create a physical volume on the partition /dev/sdc1, extend the volume group vg_web with it, then extend the logical volume lv_web by 300GB, and finally resize the filesystem with resize2fs to utilize the new space. Since the logical volume is mounted and contains data, the filesystem must be resized after extending the LV to avoid data loss. The --resizefs flag in option C would also work, but the question asks for the correct sequence without that flag, and option D explicitly includes the separate resize2fs 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

Answer

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

Question 16

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'.. Option A is correct because 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 17

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.. Option D is correct because 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.

Question 18

Which THREE commands can be used to display the UUID of a filesystem on a Linux system without superuser privileges? (Choose three.)

Accepted Answer

file -s /dev/sda1. The `file -s /dev/sda1` command reads the superblock of the specified block device and displays filesystem type information, which typically includes the UUID for filesystems like ext4, XFS, or Btrfs. This works without superuser privileges because it only performs a read-only inspection of the device file's metadata, not requiring any write access or privileged system calls.

Answer

dumpe2fs -h

Answer

findfs UUID=...

Question 19

Refer to the exhibit. The system administrator sees that /var/log is 93% full and the syslog file is nearly 2 GB. What is the most appropriate immediate action to free up disk space without losing any critical log data?

Accepted Answer

Run 'logrotate -f /etc/logrotate.conf' to force log rotation.. Option A is correct because 'logrotate -f' forces an immediate rotation of all log files as defined in /etc/logrotate.conf, which compresses or archives the current syslog file (e.g., syslog becomes syslog.1) and creates a fresh empty log file. This frees disk space without deleting any data, as the rotated logs remain on disk until the configured retention policy removes them. It is the standard, safe immediate action for a nearly full /var/log partition.

Answer

Increase the size of the /var/log partition using lvextend.

Answer

Delete /var/log/syslog and restart the syslog daemon.

Answer

Move /var/log/syslog to /tmp and create a symbolic link.

Question 20

You are a systems administrator for a medium-sized company that runs a web server on a Linux host. The server has two physical disks: /dev/sda (250 GB) and /dev/sdb (500 GB). The root filesystem is on /dev/sda2, and /var is on /dev/sda3 (50 GB). The web application stores user-uploaded files in /var/www/uploads, which is part of the /var filesystem. Recently, /var has been running out of space because uploads have grown to 40 GB. You have added /dev/sdb1 (500 GB) and created an ext4 filesystem on it. You need to make the space available for uploads without disrupting the current file paths. The server must remain online during the process. Which of the following actions should you take?

Accepted Answer

Mount /dev/sdb1 on /mnt, copy /var/www/uploads to /mnt/uploads, then mount --bind /mnt/uploads /var/www/uploads.. Option D is correct because using a bind mount allows you to mount the new 500 GB filesystem at /mnt/uploads and then bind it to /var/www/uploads, preserving the existing file paths without moving or renaming anything. This operation can be performed online without unmounting /var or disrupting the web server, as bind mounts are a feature of the Linux kernel that make a mounted filesystem accessible at another directory.

Answer

Convert /var to use LVM by backing up, reformatting, and restoring data.

Answer

Create a symbolic link from /var/www/uploads to /dev/sdb1.

Answer

Move /var/www/uploads to /mnt/uploads and create a symbolic link from /var/www/uploads to /mnt/uploads.