LFCS Storage Management Practice Test 8 — 15 Questions

Question 1

An administrator is preparing a new server that will use software RAID 1 for the root filesystem. The system has two identical 500 GB disks, /dev/sda and /dev/sdb. The administrator wants to create the RAID array and then place LVM on top of it. Which command correctly creates the RAID 1 array using the entire disks?

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

Accepted Answer

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb. Creating a RAID 1 array on whole disks requires mdadm --create with --level=1 and --raid-devices=2, followed by the device paths. RAID 1 provides mirroring for redundancy. Using --level=0 would create a stripe with no redundancy, and --assemble is only for activating existing arrays. The correct device paths are the whole disks, not partitions.

Answer

mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sda /dev/sdb

Answer

mdadm --assemble /dev/md0 /dev/sda /dev/sdb

Answer

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1

Question 2

An administrator is configuring an NFS server and wants to export /srv/data to a specific client, 192.168.10.25, with read-write access, while ensuring that the client's root user is mapped to the anonymous user for security. Which entry should be placed in /etc/exports?

Accepted Answer

/srv/data 192.168.10.25(rw,root_squash). The correct export entry must specify the exact client, grant read-write access, and enable root squashing. The entry /srv/data 192.168.10.25(rw,root_squash) accomplishes all three requirements. root_squash is the default, but explicitly including it ensures the security policy is applied even if defaults change.

Answer

/srv/data 192.168.10.25(rw,no_root_squash)

Answer

/srv/data *(rw,root_squash)

Answer

/srv/data 192.168.10.25(ro,root_squash)

Question 3

A Linux server uses LVM for its data volume /dev/vg_data/lv_app. The volume group vg_data has 30 GB of free extents and the logical volume lv_app is currently 100 GB. An administrator runs `lvextend -L +20G /dev/vg_data/lv_app` and receives a success message, but `df -h /app` still reports 100 GB. The filesystem on lv_app is ext4. Which command must the administrator run next to make the additional space usable?

Accepted Answer

resize2fs /dev/vg_data/lv_app. Extending an LVM logical volume with lvextend changes only the block device mapping; the ext4 filesystem inside keeps its original size until resized. Running resize2fs against the LV path grows the filesystem online to fill the new extents, after which df reflects the additional capacity. The XFS-only grow tool, a consistency checker, and a PV-level resize command all fail to accomplish this here.

Answer

e2fsck -f /dev/vg_data/lv_app

Answer

xfs_growfs /app

Answer

pvresize /dev/vg_data/lv_app

Question 4

A junior administrator needs to identify the UUID of the ext4 filesystem on /dev/nvme0n1p2 so it can be referenced in /etc/fstab instead of the device path. Which command displays that UUID?

Accepted Answer

blkid /dev/nvme0n1p2. blkid probes the device and reports the filesystem UUID stored in the ext4 superblock, which is exactly the value needed for an fstab entry like UUID=xxxx-... /data ext4 defaults 0 2. It works whether or not the filesystem is mounted. The other commands either display partition-table metadata or require mounting and still do not print the UUID.

Answer

lsblk -o NAME,SIZE,TYPE

Answer

fdisk -l /dev/nvme0n1p2

Answer

mount | grep nvme0n1p2

Question 5

A server has a new disk /dev/sdd that must be mounted at /backup and automatically mounted at boot. The administrator creates a GPT partition table, a single partition /dev/sdd1, and an ext4 filesystem. Which /etc/fstab entry correctly uses a persistent identifier for the filesystem?

Accepted Answer

UUID=1234-abcd /backup ext4 defaults 0 2. Persistent mounting in /etc/fstab should use a stable identifier such as UUID= or LABEL= rather than a kernel device name. The entry must also specify the correct filesystem type and avoid options like noauto that prevent boot-time mounting. The UUID form with ext4 and a pass value of 2 satisfies all requirements.

Answer

LABEL=backup /backup xfs defaults 0 2

Answer

/dev/sdd1 /backup ext4 defaults 0 2

Answer

UUID=1234-abcd /backup ext4 noauto 0 2

Question 6

A server uses LVM with volume group vg_data. The logical volume lv_app is mounted at /srv/app and is 200 GiB. The administrator adds a new 500 GiB disk, /dev/sdb, creates a physical volume on it, and extends vg_data with it. They then run lvextend -L +100G /dev/vg_data/lv_app. The filesystem is ext4. Which command must be run next to make the additional space usable without unmounting /srv/app?

Accepted Answer

resize2fs /dev/vg_data/lv_app. After extending the logical volume with lvextend, the ext4 filesystem must be grown to use the new space. resize2fs performs this online for ext4, keeping /srv/app mounted. xfs_growfs targets XFS, e2fsck checks but does not resize, and lvresize would further change the logical volume without touching the filesystem. The correct sequence is lvextend then resize2fs.

Answer

lvresize -L +100G /dev/vg_data/lv_app

Answer

e2fsck -f /dev/vg_data/lv_app

Answer

xfs_growfs /srv/app

Question 7

An administrator needs to add a new swap space to a running Linux server without rebooting. The server has a free partition /dev/sdc1 and an existing file /swapfile. Which two commands or steps are required to activate the new swap partition /dev/sdc1 immediately? (Choose two.)

Accepted Answer

swapon /dev/sdc1. To activate a new swap partition immediately, you must first initialize it with mkswap, then enable it with swapon. These two commands prepare and activate the swap space without requiring a reboot. Adding an fstab entry is for persistence across reboots, and swapoff or mount are not appropriate for enabling swap.

Answer

swapoff /dev/sdc1

Answer

mount -t swap /dev/sdc1 /mnt

Answer

echo '/dev/sdc1 none swap sw 0 0' >> /etc/fstab

Question 8

A system administrator needs to ensure that the /dev/sdb1 filesystem is automatically mounted at /data with the noatime option at boot. The filesystem's UUID is known. Which entry in /etc/fstab is correct?

Accepted Answer

UUID=1234-5678 /data ext4 defaults,noatime 0 2. The correct /etc/fstab entry must use the UUID for stable identification, specify the mount point, filesystem type, include defaults and noatime in the options, and set the dump and pass fields appropriately (0 and 2 for a non-root filesystem). The entry with UUID, defaults,noatime, 0, and 2 meets all these criteria.

Answer

UUID=1234-5678 /data ext4 noatime 0 2

Answer

/dev/sdb1 /data ext4 defaults,noatime 0 1

Answer

UUID=1234-5678 /data ext4 defaults,noatime 1 2

Question 9

A junior administrator needs to mount the XFS filesystem on /dev/sdb1 at /srv/files for the current session only, without creating a persistent entry. Which command accomplishes this?

Accepted Answer

mount -t xfs /dev/sdb1 /srv/files. A one-off mount for the current session is performed with the mount command, specifying the device, the existing mount point, and optionally the filesystem type via -t. No fstab entry is created, so the mount does not survive a reboot. Formatting tools, shell redirection into fstab, and starting nonexistent systemd units do not mount a filesystem for the current session.

Answer

systemctl start srv-files.mount

Answer

mount /dev/sdb1 /srv/files >> /etc/fstab

Answer

mkfs.xfs /dev/sdb1 /srv/files

Question 10

A junior administrator needs to add a new 2 TiB disk, /dev/sdc, to a server and create a single GPT partition that spans the entire disk. The disk currently has no partition table. Which command will create the GPT partition table and the partition in one interactive session?

Accepted Answer

gdisk /dev/sdc. To create a GPT partition table and a full-disk partition on /dev/sdc, gdisk is the dedicated interactive tool. It supports GPT natively and handles large disks. fdisk may work but is traditionally MBR-oriented, mkfs.gpt is nonexistent, and the parted command shown creates an MBR label instead of GPT. gdisk is the correct choice.

Answer

fdisk /dev/sdc

Answer

mkfs.gpt /dev/sdc

Answer

parted /dev/sdc mklabel msdos

Question 11

An administrator is troubleshooting a server with a software RAID 1 array on /dev/md0. One disk, /dev/sdc, has failed and been replaced. The administrator runs `mdadm /dev/md0 --add /dev/sdc1` and sees the array rebuilding, but after a reboot the new disk is no longer part of the array. Which action should the administrator take to ensure the replacement disk is automatically reassembled into the array at boot?

Accepted Answer

Run `mdadm --detail --scan >> /etc/mdadm.conf` and update the initramfs.. Software RAID arrays are reassembled at boot from configuration stored in /etc/mdadm.conf and embedded in the initramfs. After adding a replacement disk, the administrator must regenerate that configuration and rebuild the initramfs so the new member is recognized. Growing the array, adding the component to fstab, or relying on a manual assemble command does not provide persistent boot-time assembly.

Answer

Add an entry for /dev/sdc1 to /etc/fstab with the `nofail` option.

Answer

Run `mdadm --grow /dev/md0 --raid-devices=2` to force the array to accept the new disk.

Answer

Run `mdadm --assemble --scan` and rely on the kernel to remember the array across reboots.

Question 12

An administrator is preparing a new server with two unused disks, /dev/sdb and /dev/sdc, for a software RAID 1 array that will hold customer data. Which two commands are required to create the array and make it usable? (Choose two.)

Accepted Answer

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb /dev/sdc. Creating a usable software RAID 1 array requires two actions: mdadm --create to build the array from the member disks, and a filesystem creation command such as mkfs.ext4 on the resulting /dev/md0 device. Assembly is only for reactivating existing arrays, and pvcreate belongs to LVM. Verification with mdadm --detail is optional.

Answer

mdadm --detail /dev/md0

Answer

pvcreate /dev/sdb /dev/sdc

Answer

mdadm --assemble /dev/md0 /dev/sdb /dev/sdc

Question 13

A system administrator is troubleshooting a server that fails to boot because the root filesystem, which is on an LVM logical volume, cannot be found. The administrator suspects that the initramfs does not include the necessary LVM modules. Which command should be used to rebuild the initramfs for the currently running kernel on a Debian-based system?

Accepted Answer

update-initramfs -u. On Debian-based systems, the initramfs is managed with update-initramfs. Running update-initramfs -u regenerates the image for the current kernel, incorporating any needed modules such as LVM. Other tools like dracut or mkinitrd are used on different distributions and are not the default on Debian, and grub-mkconfig only updates the bootloader configuration.

Answer

grub-mkconfig -o /boot/grub/grub.cfg

Answer

dracut -f

Answer

mkinitrd -f /boot/initrd.img-$(uname -r)

Question 14

A Linux server has a volume group named vg_data that contains a logical volume lv_archive currently formatted with XFS and mounted at /archive. The administrator needs to shrink the logical volume to free space for a new logical volume. Which command sequence correctly reduces the size of lv_archive?

Accepted Answer

umount /archive; backup data; lvremove /dev/vg_data/lv_archive; lvcreate -L 20G -n lv_archive vg_data; mkfs.xfs /dev/vg_data/lv_archive; restore data; mount /archive. XFS filesystems cannot be shrunk. To reduce the size of an XFS logical volume, the administrator must back up the data, remove the logical volume, create a new smaller logical volume, format it with XFS, and restore the data. Any attempt to use lvreduce with -r or xfs_growfs to shrink will fail because XFS only supports growing.

Answer

umount /archive; xfs_growfs -D 20G /dev/vg_data/lv_archive; lvreduce -L 20G /dev/vg_data/lv_archive; mount /archive

Answer

umount /archive; lvreduce -L 20G /dev/vg_data/lv_archive; lvresize -r -L 20G /dev/vg_data/lv_archive; mount /archive

Answer

umount /archive; lvreduce -r -L 20G /dev/vg_data/lv_archive; mount /archive

Question 15

A junior administrator needs to mount an ISO image located at /opt/images/install.iso to the directory /mnt/iso without burning it to a physical disc. Which command should be used?

Accepted Answer

mount -o loop /opt/images/install.iso /mnt/iso. Mounting an ISO file requires the loop option so the kernel can treat the file as a block device and read its ISO9660 filesystem. The mount -o loop command is the simplest and most common way to achieve this. Alternatives like specifying only the filesystem type or using a bind mount do not correctly expose the ISO's contents.

Answer

losetup /dev/loop0 /opt/images/install.iso && mount /dev/loop0 /mnt/iso

Answer

mount --bind /opt/images/install.iso /mnt/iso

Answer

mount -t iso9660 /opt/images/install.iso /mnt/iso