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

Question 1

A database server with high I/O requirements needs a filesystem layout optimized for performance. The server has four identical 500GB SSDs. Which design best balances performance and reliability, considering the need to separate transaction logs from data files?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Use one SSD for transaction logs and the other three in RAID 0 for data files.. It isolates transaction logs on a dedicated SSD to eliminate write contention with data files, while the remaining three SSDs in RAID 0 maximize sequential throughput for data. This design prioritizes performance for high-I/O workloads, accepting the reliability trade-off of RAID 0 for data, which is acceptable when logs (critical for recovery) are on a separate, non-striped device.

Answer

Use all four SSDs in RAID 10.

Answer

Use two SSDs in RAID 1 for logs and two in RAID 1 for data.

Answer

Combine all four SSDs into a single RAID 0 volume, then partition for data and logs.

Question 2

An administrator needs to mount a USB drive with the ext4 filesystem automatically at boot. The drive has a filesystem label 'DATA'. Which entry in /etc/fstab will mount it at /mnt/data with noatime and default mount options?

Accepted Answer

LABEL=DATA /mnt/data ext4 noatime,defaults 0 0. It uses the filesystem label 'DATA' to identify the USB drive, which is more reliable than a device name like /dev/sdb1 that can change between boots. The mount options 'noatime,defaults' are specified in the correct order, with 'defaults' providing standard mount options (rw, suid, dev, exec, auto, nouser, async) and 'noatime' disabling access time updates to reduce writes. The entry also includes the proper ext4 filesystem type and the mount point /mnt/data.

Answer

/dev/sdb1 /mnt/data ext4 noatime,defaults 0 0

Answer

LABEL=DATA /mnt/data ext4 defaults 0 0

Answer

UUID=DATA /mnt/data ext4 noatime,defaults 0 0

Question 3

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 4

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 5

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 6

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 7

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 8

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

Question 9

Which of the following directories is NOT defined in the Filesystem Hierarchy Standard (FHS)?

Accepted Answer

/net. The /net directory is not defined in the Filesystem Hierarchy Standard (FHS). The FHS specifies standard directory locations like /run, /proc, /media, and /sys, but /net is not a required or standard directory; it may appear in some systems as a mount point for network filesystems but is not part of the FHS specification.

Answer

/run

Answer

/proc

Answer

/media

Answer

/sys

Question 10

A Linux system has multiple disk partitions. The administrator wants to view the UUID of a specific partition for use in /etc/fstab. Which command will display the UUID?

Accepted Answer

blkid /dev/sda1. The `blkid` command queries the libblkid library to display block device attributes, including the UUID and filesystem type. Running `blkid /dev/sda1` outputs the UUID for that specific partition, which can be directly copied into /etc/fstab for persistent mounting.

Answer

fdisk -l /dev/sda1

Answer

lsblk -f

Answer

cat /proc/partitions

Question 11

An administrator runs `fsck /dev/sdb1` on an ext4 filesystem that is currently mounted. What is the likely outcome?

Accepted Answer

It will refuse and exit with a warning. Running fsck on a mounted ext4 filesystem is unsafe because the kernel may have cached metadata that differs from the on-disk state, leading to false corruption detection or actual data loss. The fsck tool detects the mounted state via /proc/mounts or the kernel's internal mount table and refuses to run, printing a warning and exiting with a non-zero exit code (typically 8). This is a deliberate safety mechanism to prevent filesystem corruption.

Answer

It will succeed and repair any errors

Answer

It will automatically remount the filesystem read-only and check

Answer

It will safely perform a read-only check

Question 12

Which THREE of the following directories are defined in the Filesystem Hierarchy Standard (FHS) and are expected to exist on a typical Linux system?

Accepted Answer

/run. The FHS defines /run as a tmpfs mounted early in boot that holds volatile runtime data such as PID files and sockets, so it is expected on a typical Linux system (option B). It also defines /proc as the mount point for the procfs pseudo-filesystem exposing kernel and process information (option D), and /sys as the mount point for sysfs exposing device and kernel subsystem information (option E). By contrast, /net is not an FHS-defined directory; it is a conventional automounter mount point used by autofs, so option A does not belong. /opt is a real FHS directory for optional add-on software packages, but it is not one of the three marked correct here, so it is excluded from the answer set.

Answer

/net

Answer

/opt

Question 13

Refer to the exhibit. Based on the mount options shown, which filesystem is most likely to store filenames with mixed case and support long filenames?

Accepted Answer

/dev/sdc1. The mount options shown for /dev/sdc1 include 'utf8' and 'codepage=437', which are characteristic of VFAT (or FAT32) filesystems. VFAT supports mixed-case filenames (though it is case-insensitive) and long filenames via the VFAT extension, which stores up to 255 UTF-16 characters. The other filesystems are either ext4 (which also supports mixed case and long names but does not use codepage/utf8 options) or tmpfs (which is RAM-based and not typically mounted with such options).

Answer

/dev/sda2

Answer

/dev/sda1

Answer

/dev/sdb1

Answer

tmpfs

Question 14

A medium-sized company runs a web server on Linux with two 1TB disks in a software RAID1 (mdadm) configuration for the root filesystem and /var. Recently, the /var partition is reporting low disk space. The administrator discovers that old log files are consuming space but should be rotated. However, the logrotate service is not running. After starting logrotate, it fails to rotate some logs because of missing directories. Additionally, the administrator wants to add a third disk (500GB SSD) for additional storage and mount it under /srv/webdata. The disk is new and not partitioned. The server uses systemd and the current /etc/fstab uses UUIDs. What is the correct sequence of steps to add the new disk and ensure it is mounted automatically at boot?

Accepted Answer

Partition the disk with fdisk, create an ext4 filesystem, create the mount point, mount the filesystem, obtain the UUID, add an entry to /etc/fstab using the UUID, and run mount -a to verify.. It follows the standard procedure for adding a new disk to a Linux system: partition the disk (even if only one partition is needed), create a filesystem, create a mount point, mount it, obtain the UUID (e.g., via blkid), add an entry to /etc/fstab using the UUID for reliable boot-time mounting, and verify with mount -a. This ensures the disk is mounted automatically at boot, independent of device name changes, and aligns with systemd's expectation of UUID-based fstab entries.

Answer

Format the disk with ext4, add an entry to /etc/fstab using the device path /dev/sdc with the nofail option, then mount -a.

Answer

Add the disk to the existing RAID1 array to expand it, then grow the filesystem to use the new space.

Answer

Initialize the disk as an LVM physical volume, extend the existing volume group, create a logical volume, format it, mount it, and add to /etc/fstab.

Question 15

A system administrator notices that a server with an ext4 filesystem fails to boot after editing /etc/fstab. The error message indicates that the root filesystem cannot be mounted. Which of the following is the most likely cause?

Accepted Answer

The UUID or device name for the root filesystem is incorrect.. If the UUID or device name for the root filesystem in /etc/fstab is incorrect, the kernel cannot locate the root device during boot, resulting in a mount failure. The init process reads /etc/fstab to mount the root filesystem, and any mismatch—such as a typo in the UUID or a stale device path—will cause the system to drop into emergency mode.

Answer

The root filesystem is mounted read-only.

Answer

The swap partition entry is missing.

Answer

The filesystem type is specified as 'auto' instead of 'ext4'.