LPIC-2 Block Devices, Filesystems and Advanced Storage Practice Test 2 — 15 Questions

Question 1

After adding a new LUN to an existing SAN, the administrator runs multipath -ll but sees the new LUN as 'failed'. The multipathd service is running. What is the most likely cause?

Accepted Answer

The new LUN has not been presented to the host from the SAN. When a new LUN appears as 'failed' in `multipath -ll` output, the most common cause is that the LUN has not been properly presented to the host from the SAN. Even if the multipathd service is running, multipathd can only manage devices that the SCSI layer has already discovered. If the SAN administrator has not zoned or masked the LUN to the host, the host's SCSI subsystem never sees the device, so multipathd reports it as 'failed' because it cannot find the underlying paths.

Answer

The multipathd daemon needs to be restarted

Answer

The /etc/multipath.conf needs to be edited to include the new LUN

Answer

The scsi device needs to be manually created with mknod

Question 2

An administrator needs to extend an ext4 filesystem on logical volume 'home' by 5 GB. The volume group 'vg' has free extents. Which sequence of commands is correct?

Accepted Answer

lvresize -L +5G /dev/vg/home; e2fsck -f /dev/vg/home; resize2fs /dev/vg/home. The correct sequence is to first extend the logical volume by the required size using `lvresize -L +5G` (or `lvextend`), optionally check the filesystem with `e2fsck -f`, and then resize the filesystem with `resize2fs`. This ensures the filesystem can utilize the newly allocated space. Option A is incorrect because it extends by all free extents, not exactly 5 GB. Option B reverses the order, which fails because `resize2fs` cannot extend beyond the current block device. Option C uses `mount -o remount`, which does not resize the filesystem.

Answer

lvextend -l +100%FREE /dev/vg/home; resize2fs /dev/vg/home

Answer

resize2fs /dev/vg/home; lvextend -L +5G /dev/vg/home

Answer

lvextend -L +5G /dev/vg/home; mount -o remount /dev/vg/home

Question 3

A database server experiences performance degradation. Analysis shows high I/O wait on a LVM logical volume that uses striping across two physical volumes. What is the most effective way to improve performance?

Accepted Answer

Add a cache layer using lvmcache on a fast SSD. Adding a cache layer using lvmcache on a fast SSD is the most effective way to reduce high I/O wait because it places frequently accessed (hot) data on the faster SSD while keeping the bulk of data on the slower striped HDDs. This directly addresses the I/O bottleneck without requiring data migration or downtime, and it leverages the existing striped layout for sequential throughput while improving latency for random reads/writes.

Answer

Increase the stripe size and recreate the LV

Answer

Add an additional PV to the VG and extend the LV

Answer

Convert the LV to use linear mapping instead of striping

Question 4

A system's root filesystem on /dev/sda1 is offline. The administrator boots into rescue mode and needs to check the filesystem integrity. Which command should be used first?

Accepted Answer

e2fsck -p /dev/sda1. `e2fsck -p` runs an automatic, non-interactive filesystem check on the ext2/ext3/ext4 filesystem, which is the safest first step when the root filesystem is offline and the administrator is in rescue mode. The `-p` flag automatically repairs any problems that can be safely fixed without user intervention, minimizing risk of further damage. This command is specifically designed for ext-family filesystems and is the recommended initial integrity check before attempting any manual repairs.

Answer

dumpe2fs /dev/sda1

Answer

fsck.ext4 -f /dev/sda1

Answer

fsck -N /dev/sda1

Question 5

An administrator creates a new XFS filesystem on /dev/vg/data and needs to mount it at /data with noatime and a stripe unit of 1 MiB. Which /etc/fstab entry is correct?

Accepted Answer

/dev/vg/data /data xfs defaults,noatime,sunit=2048 0 0. The `sunit` mount option specifies the stripe unit in 512-byte blocks. A stripe unit of 1 MiB equals 2048 blocks (1 MiB = 1024 KiB = 2048 * 512 bytes). The `noatime` option disables access time updates. This entry correctly mounts the XFS filesystem at /data with the required parameters.

Answer

/dev/vg/data /data xfs defaults,noatime,swidth=2048 0 0

Answer

/dev/vg/data /data xfs defaults,noatime,allocsize=1m 0 0

Answer

/dev/vg/data /data xfs defaults,noatime,sunit=1024 0 0

Question 6

A storage administrator sees the following output from multipath -ll: 'dm-3 (3600605b0038f1f0019f1f7e00000000) size=10G features='0' hwhandler='0' wp=rw' but the paths are all 'failed'. The scsi devices are listed in /proc/scsi/scsi. What is the most likely cause?

Accepted Answer

The SAN fiber cables are disconnected. The output from multipath -ll shows the multipath device dm-3 with its WWID and size, but all paths are 'failed'. Since /proc/scsi/scsi lists the SCSI devices, the host bus adapters (HBAs) and drivers are functioning at the OS level. The most common cause for all paths to fail simultaneously is a physical connectivity issue, such as disconnected SAN fiber cables, which prevents the initiator from reaching the target LUNs.

Answer

The device mapper is not configured

Answer

The multipathd daemon is not running

Answer

The multipath configuration uses user_friendly_names but the bindings file is missing

Question 7

Which two commands can be used to create a swap space on a partition /dev/sdb2? (Choose two.)

Accepted Answer

mkswap /dev/sdb2. The `mkswap` command initializes a partition or file for use as swap space by writing a swap signature (UUID and superblock) to the device. Option A is correct because `mkswap /dev/sdb2` creates the swap filesystem on the specified partition. Option D is also correct because `mkswap -L swap /dev/sdb2` does the same but additionally assigns a label 'swap' to the swap area, which is a valid variant of the command.

Answer

swapon /dev/sdb2

Answer

dd if=/dev/zero of=/dev/sdb2 bs=1M count=1024

Answer

mkfs.swap /dev/sdb2

Question 8

Which two commands display information about LVM physical volumes? (Choose two.)

Accepted Answer

pvs. The `pvs` command (option A) provides a concise, configurable listing of all LVM physical volumes, showing key attributes like PV name, VG name, size, and free space. The `pvdisplay` command (option E) offers a detailed, verbose display of physical volume properties, including metadata areas, PE size, and allocation status. Both are standard LVM utilities for querying PV information.

Answer

pvcreate

Answer

pvck

Answer

pvscan

Question 9

Which three conditions must be met for a filesystem to be mounted by UUID in /etc/fstab? (Choose three.)

Accepted Answer

The UUID must be present in /dev/disk/by-uuid/. The Linux kernel and udev create symbolic links in /dev/disk/by-uuid/ for each block device that has a UUID. When /etc/fstab specifies a filesystem by UUID, the mount command resolves the UUID by looking up the corresponding symlink in this directory. If the symlink is missing (e.g., due to a missing udev rule or a corrupted device), the mount will fail.

Answer

The blkid command must have been run at least once

Answer

The UUID must be listed in the kernel's boot parameters

Question 10

Refer to the exhibit. The administrator wants to mount /dev/sdb1 at /data using its UUID. Which /etc/fstab entry is correct?

Accepted Answer

UUID=ijkl-9012 /data ext4 defaults 0 0. The administrator wants to mount /dev/sdb1 using its UUID, and the exhibit (not shown) indicates that the UUID of /dev/sdb1 is 'ijkl-9012'. The correct /etc/fstab syntax uses the 'UUID=' prefix followed by the actual UUID value, the mount point, filesystem type, options, dump, and pass fields. This ensures the filesystem is identified by its universally unique identifier, which remains stable even if the device name changes.

Answer

/dev/sdb1 /data ext4 defaults 0 0

Answer

PARTUUID=ijkl-9012 /data ext4 defaults 0 0

Answer

UUID=12345678-01 /data ext4 defaults 0 0

Question 11

Refer to the exhibit. The /data filesystem is nearly full. The administrator has added a new disk /dev/sdc with 10GB capacity. The VG currently has no free space. Which steps will increase the available space for /data using LVM and ext4?

Accepted Answer

pvcreate /dev/sdc; vgextend vg /dev/sdc; lvextend -l +100%FREE /dev/vg/data; resize2fs /dev/vg/data. It follows the proper LVM workflow: create a physical volume (pvcreate), add it to the volume group (vgextend), extend the logical volume using all free space in the VG (lvextend -l +100%FREE), and then resize the ext4 filesystem (resize2fs). This ensures the new 10GB disk is fully utilized for /data.

Answer

vgextend vg /dev/sdc; lvextend -L +10G /dev/vg/data; resize2fs /dev/vg/data

Answer

pvcreate /dev/sdc; lvextend -L +10G /dev/vg/data; resize2fs /dev/vg/data

Answer

pvcreate /dev/sdc; vgextend vg /dev/sdc; lvextend -l +50%FREE /dev/vg/data; resize2fs /dev/vg/data

Question 12

Refer to the exhibit. A system administrator wants to replace disk sdb1 in the RAID1 array. After physically removing sdb, which sequence of commands should be used?

Accepted Answer

mdadm /dev/md0 --fail /dev/sdb1; mdadm /dev/md0 --remove /dev/sdb1; mdadm /dev/md0 --add /dev/sdd1; mdadm --manage /dev/md0 --run. After physically removing the failed disk (sdb), the administrator must first mark the device as failed using `--fail`, then remove it with `--remove`, add the new disk (sdd1) with `--add`, and finally run `--run` to ensure the array is activated if it was stopped or degraded. The `--run` flag is necessary because a RAID1 array with a missing device may not automatically start; this command forces the array to become active so the rebuild can begin. Note that the question does not involve filesystem extension; the focus is on the correct sequence for replacing a disk in a RAID array.

Answer

mdadm /dev/md0 --remove /dev/sdb1; mdadm /dev/md0 --add /dev/sdd1

Answer

mdadm /dev/md0 --fail /dev/sdb1; mdadm /dev/md0 --remove /dev/sdb1; mdadm /dev/md0 --add /dev/sdd1

Answer

mdadm /dev/md0 --fail /dev/sdb1; mdadm /dev/md0 --remove /dev/sdb1; mdadm --grow /dev/md0 --add /dev/sdd1; mdadm --manage /dev/md0 --run

Question 13

A system administrator notices that a new iSCSI target is not appearing as a block device after running iscsiadm. The target is known to be online and reachable. What is the most likely cause?

Accepted Answer

The iSCSI service (iscsid) is not running.. The iSCSI initiator requires the `iscsid` daemon to be running in order to process discovery and login requests from `iscsiadm`. Even if the target is online and reachable, without the `iscsid` service, the kernel's iSCSI layer cannot establish a session or create the corresponding block device (e.g., /dev/sdX). This is the most likely cause because the administrator has confirmed network connectivity and target availability, leaving the service state as the primary suspect.

Answer

The iSCSI initiator name is not set.

Answer

The target IQN is not specified correctly.

Answer

The network interface is down.

Question 14

Which command can be used to create a swap partition on /dev/sdb1?

Accepted Answer

mkswap /dev/sdb1; swapon /dev/sdb1. B is correct because creating a swap partition requires two steps: first, `mkswap` initializes the partition as a swap area by writing a swap signature (UUID and superblock) to /dev/sdb1; second, `swapon` activates the swap space, making it available to the kernel for paging. Without `mkswap`, the partition lacks the necessary swap metadata and cannot be used.

Answer

swapcreate /dev/sdb1

Answer

swapon /dev/sdb1

Answer

mkfs.swap /dev/sdb1

Question 15

An administrator wants to convert an ext4 filesystem to Btrfs without losing data. Which procedure should be used?

Accepted Answer

btrfs-convert /dev/sda1. The correct procedure is to use `btrfs-convert /dev/sda1`, which is a dedicated tool that performs an in-place conversion of an existing ext2/3/4 filesystem to Btrfs while preserving all existing data. It works by creating a Btrfs filesystem that wraps the original ext4 data structures, then allowing a gradual migration to native Btrfs features via a background process.

Answer

mkfs.btrfs /dev/sda1

Answer

cp -a /mnt/ext4 /mnt/btrfs

Answer

btrfs device add /dev/sda1 /mnt