EX200 Configure local storage Practice Test 2 — 15 Questions

Question 1

Match each systemd unit type to its purpose.

Accepted Answer

service: Manages daemon processes. Systemd unit types define system resources: service (daemons), socket (IPC), target (group/synchronization), timer (scheduled activation). Common confusions involve mixing mount with service and target with timer.

Answer

service: Manages file system mount points

Answer

timer: Groups units to define synchronization points

Question 2

Match each cron syntax field to its meaning.

Accepted Answer

minute: 0-59. The five fields in a cron syntax are (in order): minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7). Common confusions include swapping the minute and hour ranges.

Answer

minute: 0-23

Question 3

Which command initializes a disk partition as a physical volume for LVM?

Accepted Answer

pvcreate. `pvcreate` is the LVM command specifically designed to initialize a disk partition as a physical volume (PV), which is the first step in creating an LVM logical volume. Without a PV, LVM cannot manage the underlying block device. The command writes LVM metadata to the partition, marking it as available for inclusion in a volume group.

Answer

fdisk

Answer

vgcreate

Answer

lvcreate

Question 4

Which command shows the amount of disk space used and available on each mounted filesystem?

Accepted Answer

df -h. The `df -h` command displays disk space usage for all mounted filesystems, showing total, used, and available space in human-readable format (e.g., GB, MB). This directly answers the question about disk space on each mounted filesystem.

Answer

fdisk -l

Answer

du -sh

Answer

lsblk

Question 5

Which file contains the list of filesystems to be mounted at system startup?

Accepted Answer

/etc/fstab. The /etc/fstab file is the system configuration file that defines static filesystem information, including devices, mount points, filesystem types, mount options, dump frequency, and fsck pass order. During system startup, the mount -a command (typically run by systemd or init scripts) reads /etc/fstab to mount all filesystems listed there, making it the definitive source for automatic mounting at boot.

Answer

/etc/rc.local

Answer

/etc/filesystems

Answer

/etc/mtab

Question 6

After adding a new disk to a volume group, which command is used to extend a logical volume by 2GB?

Accepted Answer

lvextend -L +2G /dev/vg/lv. After adding a new disk to a volume group, the `lvextend -L +2G /dev/vg/lv` command extends the logical volume by exactly 2 GB. The `-L +2G` syntax specifies the additional size to add, and the target is the logical volume path. This is the standard LVM command for increasing logical volume size without specifying a physical extent range.

Answer

vgextend vg /dev/sdb

Answer

resize2fs /dev/vg/lv

Answer

pvcreate /dev/sdb

Question 7

A filesystem reports 0% free space in df -h, but when checking the directory size with du -sh, it shows much less usage. What is the most likely cause?

Accepted Answer

Deleted files still held open by processes. When a file is deleted while a process still holds an open file descriptor to it, the file's data blocks remain allocated on disk and are not freed until the process closes the descriptor. The `df` command reports disk usage based on the filesystem's block allocation, which still counts those blocks as used, while `du` calculates usage by walking the directory tree and cannot see the deleted file's data, leading to the discrepancy.

Answer

Filesystem is corrupted

Answer

The disk has bad sectors

Answer

Filesystem is mounted with noexe

Question 8

Which command is used to display all block devices that have a filesystem of type XFS?

Accepted Answer

blkid -t TYPE=xfs. The `blkid -t TYPE=xfs` command queries the libblkid library to list all block devices whose filesystem type is exactly XFS. It directly filters by the TYPE attribute, making it the most precise tool for this specific task.

Answer

lsblk -f

Answer

findmnt -t xfs

Answer

df -t xfs

Question 9

Which of the following is true regarding shrinking logical volumes?

Accepted Answer

XFS filesystems cannot be shrunk. B is correct because XFS filesystems do not support shrinking. The XFS design is based on allocation groups and a log-structured metadata layout that makes online or offline shrinking infeasible without significant filesystem restructuring. This is a fundamental limitation of XFS, unlike ext4 which can be shrunk offline.

Answer

You can reduce a volume while it is mounted if you use resize2fs

Answer

Reducing an LVM volume is a simple process

Answer

Ext4 filesystems support online shrinking

Question 10

A system administrator tries to mount a filesystem but receives the error: 'mount: /dev/sdb1 is already mounted or /data busy'. The filesystem is not listed in the mount output. What is the most likely cause?

Accepted Answer

The mount point /data is in use by a process. The error message 'mount: /dev/sdb1 is already mounted or /data busy' indicates that the mount point /data is currently in use by a process, preventing the mount operation. Even though the filesystem is not listed in the mount output, a process may have an open file descriptor or be using /data as its current working directory, which keeps the directory busy. The 'lsof' or 'fuser' commands can be used to identify the offending process.

Answer

The kernel does not have the filesystem driver loaded

Answer

The device is already mounted on another mount point

Answer

The filesystem is corrupted

Question 11

Which of the following is the correct way to persistently mount a filesystem using its UUID?

Accepted Answer

UUID=1234 /mnt xfs defaults 0 0. The /etc/fstab entry uses the 'UUID=' prefix followed by the actual UUID value to persistently mount a filesystem. The kernel reads this line at boot time and resolves the UUID to the corresponding block device, ensuring the mount is consistent regardless of device name changes.

Answer

LABEL=1234 /mnt xfs defaults 0 0

Answer

/dev/disk/by-uuid/1234 /mnt xfs defaults 0 0

Answer

PARTUUID=1234 /mnt xfs defaults 0 0

Question 12

Which THREE of the following are valid methods to identify a block device in /etc/fstab?

Accepted Answer

LABEL. While /dev/sda1 and /dev/disk/by-path/... are actually valid device paths that mount can use in /etc/fstab, they are not recommended because they are not persistent across reboots if device names change. The persistent identifiers supported for fstab include UUID, LABEL, PARTUUID, and PARTLABEL. Therefore, the three persistent identifiers among the options are B, C, and D.

Answer

by-path

Answer

/dev/sda1

Question 13

Which TWO commands can be used to view the current disk usage of a filesystem?

Accepted Answer

du. The `du` command (disk usage) estimates file and directory space usage, allowing you to view disk usage at the file or directory level. The `df` command (disk free) reports the amount of available and used disk space on mounted filesystems, showing overall filesystem usage. Both are standard Linux tools for examining disk consumption.

Answer

blkid

Answer

fdisk

Answer

lsblk

Question 14

Refer to the exhibit. If the system administrator wants to create a new logical volume of size 2GB in the 'rhel' volume group, what is the first command that must be executed?

Accepted Answer

pvcreate /dev/sdb1. Before a new logical volume can be created in the 'rhel' volume group, the physical volume must be prepared. The exhibit shows that /dev/sdb is not yet partitioned; the first step is to create a partition (e.g., /dev/sdb1) and then initialize it as a physical volume using `pvcreate /dev/sdb1`. Only after this can the volume group be extended and the logical volume created.

Answer

pvcreate /dev/sdb

Answer

lvcreate -L 2G -n lvdata rhel

Answer

vgextend rhel /dev/sdb

Question 15

Refer to the exhibit. A user tries to execute a script located in /data/script.sh but gets 'Permission denied'. The script has execute permissions. What is the most likely cause?

Accepted Answer

The filesystem is mounted with noexec. The most likely cause is that the filesystem where /data resides is mounted with the 'noexec' option. This mount option prevents the execution of any binary or script directly from that filesystem, regardless of the file's individual execute permissions. The 'noexec' flag is commonly set on partitions like /tmp or /var for security reasons, and it overrides the file's permission bits.

Answer

The filesystem is full

Answer

SELinux is blocking execution

Answer

The script is in a directory with noexec