LPIC-1 Devices, Filesystems and FHS Practice Test 3 — 15 Questions

Question 1

A system fails to mount an XFS filesystem with the entry in /etc/fstab. The entry looks correct. Which fstab field might be missing or incorrect?

Accepted Answer

The filesystem type field. The XFS filesystem requires the filesystem type field in /etc/fstab to be explicitly set to 'xfs'. If this field is missing or incorrect (e.g., left blank, set to 'auto', or mistyped as 'ext4'), the mount command will fail because it cannot determine the correct filesystem driver to use. Even if the device, mountpoint, and options appear correct, an incorrect or missing type field prevents the kernel from loading the XFS module and mounting the filesystem.

Answer

The device field

Answer

The options field

Answer

The mountpoint field

Question 2

After running 'df -h', the administrator sees that /dev/sda1 is 100% used. 'du -sh /mountpoint' shows only 50% used. What is the most likely cause?

Accepted Answer

A large file was deleted but a process still holds it open. When a file is deleted but a process still holds an open file descriptor to it, the kernel does not release the disk space until the process closes the file. The 'df' command reports space usage based on the filesystem's superblock, which still counts the deleted file's blocks. 'du' calculates space by traversing the directory tree and summing file sizes, so it does not see the unlinked file. This discrepancy explains why 'df' shows 100% usage while 'du' shows only 50%.

Answer

The disk has bad blocks

Answer

There is a hard link that du does not count

Answer

The filesystem is corrupted and needs fsck

Question 3

Which directory under the root filesystem is defined by FHS as containing variable data that may change in size, such as logs and spools?

Accepted Answer

/var. The Filesystem Hierarchy Standard (FHS) defines /var as the directory for variable data that changes in size during normal system operation, including log files (e.g., /var/log), spool directories (e.g., /var/spool/mail), and temporary files that persist across reboots. This is distinct from /tmp, which is cleared on reboot, and /run, which holds runtime variable data that is volatile and cleared at boot.

Answer

/opt

Answer

/run

Answer

/tmp

Question 4

A disk is partitioned with GPT. The administrator wants to see the partition type GUIDs and partition UUIDs. Which command is most appropriate?

Accepted Answer

gdisk -l /dev/sda. `gdisk -l /dev/sda` is the GPT-specific partitioning tool that displays partition type GUIDs (e.g., EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 for Microsoft basic data) and partition unique GUIDs (UUIDs) for each partition on a GPT disk. Unlike MBR tools, GPT stores these 128-bit identifiers in the partition table headers, and `gdisk` is designed to read and present them directly.

Answer

blkid /dev/sda

Answer

lsblk -f /dev/sda

Answer

fdisk -l /dev/sda

Question 5

After a system crash, the root filesystem (ext4) is mounted read-only and the administrator needs to perform an interactive check. Which command should be used?

Accepted Answer

fsck -r /dev/sda1. The `-r` flag in `fsck` performs an interactive repair, prompting the administrator for a yes/no decision before fixing each filesystem issue. This is exactly what is needed after a crash when the root filesystem is mounted read-only and the administrator wants to manually check and decide on repairs. The `-r` flag is the standard way to invoke interactive mode for ext4 filesystems.

Answer

fsck -n /dev/sda1

Answer

fsck -y /dev/sda1

Answer

fsck -a /dev/sda1

Question 6

According to FHS, which directory should NOT be mounted on a networked filesystem (e.g., NFS) because it contains host-specific configuration files?

Accepted Answer

/etc. The Filesystem Hierarchy Standard (FHS) specifies that /etc contains host-specific configuration files that must be local to each machine. Mounting /etc over a network filesystem like NFS would cause all clients to share the same configuration, breaking system identity, network settings, and security policies. This violates the FHS requirement that /etc be a local filesystem.

Answer

/home

Answer

/var

Answer

/opt

Question 7

Which TWO commands can be used to display information about block devices such as disks and partitions? (Choose exactly two.)

Accepted Answer

blkid. `blkid` retrieves attributes like UUID and filesystem type from block devices by reading their superblocks, making it ideal for identifying disks and partitions. `fdisk -l` lists partition tables, displaying detailed information about disk layouts and partitions. Both commands are directly focused on block device information. In contrast, `lsblk` lists all block devices in a tree, but it is more about displaying device hierarchy than partition-specific details. `df` shows filesystem disk usage of mounted filesystems, not raw device info. `mount` displays mounted filesystems, not block devices.

Answer

lsblk

Answer

df

Answer

mount

Question 8

Which THREE of the following filesystem types are journaling filesystems? (Choose exactly three.)

Accepted Answer

ext4. ext4 is a journaling filesystem that uses a journal to record metadata changes before they are written to the main filesystem, ensuring consistency after a crash. It is the default filesystem for many Linux distributions and supports features like extents and delayed allocation.

Answer

ext2

Answer

VFat

Question 9

Refer to the exhibit. How many physical disks are present in the system?

Accepted Answer

2. The output shows two SCSI disks: /dev/sda and /dev/sdb. Each device file represents a physical disk, so there are exactly two physical disks present. The partitions (sda1, sda2, sdb1) are subdivisions of those disks and do not count as separate physical disks.

Answer

3

Answer

4

Answer

1

Question 10

Refer to the exhibit. On boot, which filesystem will be checked first by fsck?

Accepted Answer

The root filesystem (/). The root filesystem (/) is checked first by fsck because it is mounted read-only during the initial boot phase, and fsck must verify its integrity before the system can proceed to mount other filesystems. The order of filesystem checks is determined by the fs_passno field in /etc/fstab, where the root filesystem typically has a passno of 1, ensuring it is checked before any filesystem with a higher passno value.

Answer

The swap partition

Answer

The CD-ROM device

Answer

The /boot filesystem

Question 11

Refer to the exhibit. The root filesystem is nearly full. The administrator needs to increase its size. Which steps should be performed?

Accepted Answer

Use lvextend to extend the logical volume and then resize2fs to resize the filesystem. The root filesystem is on an LVM logical volume, as indicated by the exhibit (e.g., /dev/mapper/rootvg-rootlv). To increase its size, you must first extend the logical volume using lvextend, then resize the filesystem with resize2fs. This two-step process ensures the underlying block device and the filesystem are both enlarged to utilize the newly available space.

Answer

Use parted to resize the root partition and then mount it

Answer

Use fdisk to increase the size of /dev/sda1 and then run resize2fs

Answer

Create a new filesystem on /dev/sda2 and mount it to /

Question 12

A Linux technician receives a report that a USB flash drive inserted into a system is not automatically detected. Which command should the technician use to verify if the device is recognized by the kernel?

Accepted Answer

dmesg | tail. The `dmesg | tail` command displays kernel ring buffer messages, which include real-time hardware detection events such as USB device insertion. When a USB flash drive is plugged in, the kernel logs messages about device recognition, driver binding, and assigned device nodes (e.g., /dev/sdb). This makes it the most direct way to verify if the kernel has detected the device.

Answer

fdisk -l

Answer

lsusb

Answer

blkid

Question 13

A system administrator wants to ensure that the filesystem on /dev/sdb1 is checked for errors every 30 mounts. Which command accomplishes this?

Accepted Answer

tune2fs -c 30 /dev/sdb1. The `tune2fs` command is used to adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems. The `-c` option sets the maximum mount count between filesystem checks; `tune2fs -c 30 /dev/sdb1` configures the filesystem to trigger an `fsck` check every 30 mounts. This is the correct tool for modifying this persistent setting.

Answer

fsck -c 30 /dev/sdb1

Answer

e2fsck -c 30 /dev/sdb1

Answer

mount -o errors=remount-ro

Question 14

An administrator needs to mount an ISO file located at /tmp/data.iso to /mnt/iso for read-only access. Which command should be used?

Accepted Answer

mount -o loop,ro /tmp/data.iso /mnt/iso. It uses the `-o loop,ro` options to mount the ISO file as a loop device with read-only access. The `loop` option is required to mount a file as a block device, and `ro` ensures the filesystem is mounted read-only, which is appropriate for an ISO image (typically an iso9660 filesystem).

Answer

mount /tmp/data.iso /mnt/iso

Answer

mount -t iso9660 -o loop /tmp/data.iso /mnt/iso

Answer

mount -o ro,loop /mnt/iso /tmp/data.iso

Question 15

A server has a partition /dev/sda2 that is almost full. The admin suspects a large file has been deleted but is still held open by a process. Which command can identify such a file?

Accepted Answer

lsof | grep deleted. The `lsof` command lists open files and their associated processes. When a file is deleted but still held open by a process, `lsof` shows the filename with a '(deleted)' marker in its output. Piping through `grep deleted` filters for exactly those entries, allowing the admin to identify the file and the process keeping it alive, which is the precise scenario described.

Answer

du -sh /

Answer

find / -size +100M

Answer

df -h