LPIC-1 Devices, Filesystems and FHS Practice Test 5 — 15 Questions

Question 1

A technician runs 'blkid' and sees output like '/dev/sda2: UUID="abc-def-ghi" TYPE="ext4"'. Which command can mount this partition using its UUID?

Accepted Answer

mount -U "abc-def-ghi" /mnt. The 'mount' command supports the '-U' option to specify a partition by its UUID, which is a unique identifier for the filesystem. This allows mounting without relying on device names like /dev/sda2, which can change across reboots. The UUID is taken directly from the 'blkid' output.

Answer

mount -I "abc-def-ghi" /mnt

Answer

mount /dev/sda2 /mnt

Answer

mount -L "abc-def-ghi" /mnt

Question 2

A system reports 'No space left on device' but 'df -h' shows only 60% usage. Which command would help identify the cause?

Accepted Answer

df -i. The 'No space left on device' error can also occur when the filesystem runs out of inodes, even if disk space is not full. The command 'df -i' shows inode usage; if inodes are exhausted, no new files can be created, causing the error. 'lsof +L1' lists deleted open files, which consume disk blocks but not inodes, so it is not the right tool when disk space is only 60% used.

Answer

stat /

Answer

lsof +L1

Answer

du -sh /

Question 3

An administrator plans to back up the /home filesystem using dump. Which option to dump is required to perform a full backup?

Accepted Answer

-0. The dump utility uses dump levels (0-9) to control backup depth. A level 0 dump performs a full backup of the specified filesystem, copying all files regardless of modification time. This is the required option for a complete backup of /home.

Answer

-f /dev/st0

Answer

-u

Answer

-1

Question 4

The /proc filesystem is described as a virtual filesystem. Which statement best describes its purpose?

Accepted Answer

It provides an interface to kernel data structures and processes.. The /proc filesystem is a virtual filesystem that does not contain actual files on disk but instead provides a runtime interface to kernel data structures, including process information, system memory, CPU details, and hardware configuration. This allows users and system tools (like ps, top, and free) to read kernel state in real time without needing direct kernel memory access.

Answer

It contains configuration files for system services.

Answer

It holds binary executables for system administration.

Answer

It stores temporary files that survive reboots.

Question 5

An ext4 filesystem is experiencing performance degradation due to very frequent small writes. Which tune2fs option can help by reserving a percentage of blocks for the root user to prevent fragmentation?

Accepted Answer

-g root. The -g option in tune2fs sets the group that can use the reserved blocks. By specifying 'root', it assigns the reserved blocks to the root group, ensuring that the root user can access this reserved space. This helps prevent fragmentation by keeping free blocks available for root's small writes, rather than allowing the filesystem to become completely full. Options A and C are unrelated to block reservation. Option D sets the reserved block percentage to 0, which does not reserve any blocks and can actually increase fragmentation.

Answer

-i 0

Answer

-c 0

Answer

-m 0

Question 6

Which TWO statements about udev rules are correct? (Choose two.)

Accepted Answer

Custom udev rules should be placed in /etc/udev/rules.d/.. Custom udev rules are placed in /etc/udev/rules.d/ to override or supplement the default rules in /lib/udev/rules.d/. This directory is the standard location for system administrators to add persistent device naming or custom actions without modifying distribution-provided files.

Answer

Udev rules are only applied at boot time.

Answer

Udev rules can be used to schedule periodic tasks via cron.

Answer

The 'udevadm verify' command tests rule syntax.

Question 7

Which THREE of the following directories are part of the FHS and must be present on a standard Linux system? (Choose three.)

Accepted Answer

/var. /var is required by the FHS to store variable data such as logs (/var/log), mail spools, and print queues. It must exist on a standard Linux system because many core services depend on it for runtime data that changes in size and content.

Answer

/lost+found

Answer

/home

Question 8

Which TWO options in /etc/fstab affect whether a filesystem is mounted at boot? (Choose two.)

Accepted Answer

auto. The 'auto' option (C) explicitly tells the system to mount the filesystem automatically at boot time via `mount -a` (as run by systemd or init scripts). Conversely, 'noauto' (E) prevents automatic mounting at boot, requiring manual intervention. Both directly control boot-time behavior in /etc/fstab.

Answer

user

Answer

defaults

Answer

ro

Question 9

Refer to the exhibit. An administrator wants to add a new partition that uses the remaining space on /dev/sda (total 40GB). What is the next free sector for the start of the new partition?

Accepted Answer

83886080. The disk has 40 GB, which is 83886080 sectors, numbered 0–83886079. The existing partition(s) end at sector 83886079, so the next free sector would be 83886080. Although this sector is beyond the disk, it is the correct arithmetic answer and indicates that no free space remains. Therefore, option A is correct.

Answer

83886079

Answer

83886078

Answer

0

Question 10

Refer to the exhibit. The system logs show the above messages. What is the most likely cause and the correct first action?

Accepted Answer

Filesystem corruption occurred; unmount and run fsck.. The kernel log messages indicate a filesystem I/O error (e.g., 'EXT4-fs error (device sda1)') which typically points to filesystem corruption. Running fsck on the unmounted filesystem is the correct first action to repair the metadata and recover the filesystem. Option B is correct because fsck is the standard tool for checking and repairing filesystem inconsistencies.

Answer

The filesystem is read-only; remount with 'mount -o remount,rw /'.

Answer

The device is unresponsive; replace the disk.

Answer

The filesystem is full; delete unnecessary files.

Question 11

Refer to the exhibit. An administrator notices that /proc is mounted with 'noexec'. What is the impact of this mount option?

Accepted Answer

No binaries can be executed directly from /proc.. The 'noexec' mount option prevents the direct execution of any binary files located on the mounted filesystem. Since /proc is a virtual filesystem that contains runtime system information and process data, mounting it with 'noexec' means that no binaries can be executed directly from /proc. This is a security measure to prevent malicious code from being run from procfs, as /proc should never contain executable programs in normal operation.

Answer

Device files are not interpreted.

Answer

Setuid programs do not work.

Answer

The filesystem cannot be written to.

Question 12

A technician is repairing a system and needs to mount the root filesystem from a different disk to /mnt/sysroot. The partition is /dev/sda2 with an ext4 filesystem. Which command should be used?

Accepted Answer

mount /dev/sda2 /mnt/sysroot. The `mount` command with the device and mount point as arguments automatically detects the filesystem type (e.g., ext4) and mounts the partition at the specified directory. This is the standard way to mount a root filesystem from a different disk for repair purposes.

Answer

mount -o loop /dev/sda2 /mnt/sysroot

Answer

mount -a

Answer

mount -t ext4 /dev/sda2 /mnt

Question 13

An administrator notices that a large file on an ext4 filesystem is taking up more disk space than expected based on its size. Which command would show the actual disk usage (block allocation) of the file?

Accepted Answer

du -h. (du -h) is correct because du (disk usage) reports the actual disk space consumed by a file, including allocated blocks, which can be larger than the file's logical size due to block size overhead, fragmentation, or sparse file handling. On ext4, the default block size is 4096 bytes, so a 1-byte file occupies 4096 bytes on disk, and du reflects this allocation.

Answer

ls -l

Answer

df -h

Answer

stat

Question 14

A Linux system fails to boot with the error 'Kernel panic: VFS: Unable to mount root fs on unknown-block(0,0)'. After investigation, the administrator suspects that the root filesystem device is not being detected. Which of the following is the most likely cause?

Accepted Answer

The root= kernel parameter points to a non-existent device. The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates the kernel cannot locate the device specified by the 'root=' kernel parameter. If this parameter points to a non-existent device (e.g., wrong partition number or missing disk), the kernel fails to mount the root filesystem, causing a panic. This is the most direct cause among the options.

Answer

The root filesystem is corrupted

Answer

The initrd file is missing or corrupted

Answer

The SATA controller driver is not included in the kernel

Question 15

An application assumes its data is stored in /opt/app/data, but the /opt filesystem is running out of space. The administrator moves the data to /var/app/data. Which method will allow the application to continue accessing the data at /opt/app/data without modifying the application's configuration?

Accepted Answer

Use mount --bind /var/app/data /opt/app/data. `mount --bind` creates a bind mount that makes the contents of `/var/app/data` appear at `/opt/app/data` without moving or copying files. The application continues to access the data at the original path, and the kernel transparently redirects all filesystem operations to the new location. This avoids modifying the application's configuration or creating a symbolic link that might not be followed by all programs (e.g., those using `chroot` or running with restricted permissions).

Answer

Use ln -s /var/app/data /opt/app/data

Answer

Edit /etc/fstab to mount /var/app/data at /opt/app/data

Answer

Create a symbolic link /opt/app/data -> /var/app/data