LFCS Storage Management Practice Test 7 — 15 Questions

Question 1

A Linux server at a hosting provider uses a software RAID 5 array with three 2 TB disks (sda, sdb, sdc) configured as /dev/md0, hosting a large ext4 filesystem. The server experiences a performance degradation and I/O errors. The administrator checks /proc/mdstat and sees that /dev/sda is marked as failed. The remaining two disks are still active. The administrator has a spare disk /dev/sdd of the same size. The filesystem is sparse and can tolerate downtime. What is the most appropriate course of action to restore the array to a fully functional state with redundancy?

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

Accepted Answer

Run 'mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda', then 'mdadm --manage /dev/md0 --add /dev/sdd'.. The correct procedure is to mark the failed disk as failed (if not already), remove it from the array, then add the spare disk /dev/sdd. This allows mdadm to rebuild the RAID 5 array onto the new disk, restoring redundancy. The commands 'mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda' followed by 'mdadm --manage /dev/md0 --add /dev/sdd' accomplish this safely.

Answer

Recreate the RAID 5 array from scratch using all three healthy disks (sdb, sdc, sdd) and restore data from backup.

Answer

Run 'mdadm --manage /dev/md0 --add /dev/sdd' to directly add the new disk and let the array rebuild automatically.

Answer

Use LVM to mirror the two healthy disks and ignore the failed one, ensuring data redundancy.

Question 2

A Linux server has a single XFS filesystem mounted at /data on /dev/sdb1. The storage array behind /dev/sdb1 is expanded and the block device is now 2 TB instead of 1 TB. The administrator confirms that the kernel sees the larger device with blockdev --getsize64 /dev/sdb1. Which command should be run to make the additional space usable by the mounted /data filesystem?

Accepted Answer

xfs_growfs /data. XFS filesystems are extended with the xfs_growfs command, which operates on a mounted filesystem using its mount point. Because the block device already reports the larger size, the only remaining step is to grow the XFS filesystem into that free space. Tools such as resize2fs target ext-family filesystems, while xfs_repair and growpart address different problems, so they cannot satisfy this requirement.

Answer

growpart /dev/sdb 1

Answer

resize2fs /dev/sdb1

Answer

xfs_repair /dev/sdb1

Question 3

A file server has an XFS filesystem on /dev/vg_data/lv_share that is nearly full. The volume group has 50 GB of free space. The administrator runs lvextend -L +20G /dev/vg_data/lv_share, which succeeds. However, df -h still reports the original size. What should the administrator do next to make the additional space usable?

Accepted Answer

Run xfs_growfs /mountpoint, where /mountpoint is the current mount point of the filesystem.. After extending an LV that hosts an XFS filesystem, the filesystem itself must be grown separately. The XFS-specific tool is xfs_growfs, which is invoked with the mount point and can be run while the filesystem is mounted. This expands the filesystem to use the additional space, after which df will show the new size.

Answer

Run partprobe /dev/vg_data/lv_share to make the kernel reread the partition table.

Answer

Run resize2fs /dev/vg_data/lv_share to expand the filesystem to the new size.

Answer

Unmount the filesystem, run lvresize --resizefs /dev/vg_data/lv_share, then remount it.

Question 4

A junior administrator has installed a new 4 TB SATA disk as /dev/sdb on a RHEL 9 server and wants to use it as a single XFS filesystem mounted at /data. The disk currently has no partition table. Which command should be run first to create an XFS filesystem directly on the whole device?

Accepted Answer

mkfs.xfs /dev/sdb. Creating an XFS filesystem on a raw block device is done with mkfs.xfs followed by the device path. Because the new 4 TB disk has no partition table and the requirement is a single filesystem spanning the entire device, targeting /dev/sdb directly is correct. Partitioning is optional when the whole disk is dedicated to one filesystem.

Answer

mkfs -t xfs /dev/sdb1

Answer

xfs_growfs /dev/sdb

Answer

fdisk /dev/sdb && mkfs.xfs /dev/sdb

Question 5

An administrator manages a server with several iSCSI LUNs attached. The server reboots after a kernel update, and one of the LUNs, which previously appeared as /dev/sdc, is now enumerated as /dev/sdd, breaking an /etc/fstab entry that references /dev/sdc. The administrator wants to make the mount configuration resilient to device-name changes and to avoid boot delays if the LUN is temporarily missing. Which two actions should the administrator take? (Choose two.)

Accepted Answer

Add the nofail mount option to the /etc/fstab entry for that filesystem.. Persistent identifiers such as UUIDs or by-path symlinks decouple the mount configuration from the kernel's enumeration order, and nofail prevents a temporarily missing iSCSI LUN from delaying or blocking boot. Together they make the fstab entry resilient to device renumbering. Changing to a device-mapper path, adding _netdev, or forcing a udev rename do not address enumeration stability and can introduce new problems.

Answer

Add the _netdev mount option to the /etc/fstab entry and rely on the device name /dev/sdc.

Answer

Change the mount point to use the device-mapper path /dev/mapper/sdc1 instead of /dev/sdc.

Answer

Create a udev rule that renames the LUN to /dev/sdc every time it is detected.

Question 6

A junior administrator has a USB flash drive at /dev/sdb that will be used exclusively as a data disk on a Linux server. They need to create an XFS filesystem on the whole device (no partitions). Which command accomplishes this?

Accepted Answer

mkfs.xfs /dev/sdb. Creating an XFS filesystem on a whole block device is done with the mkfs.xfs command followed by the device path. XFS is commonly used for data volumes and supports being placed directly on an unpartitioned disk. The other commands either grow or repair an existing XFS filesystem and cannot initialize a new one.

Answer

xfs_growfs /dev/sdb

Answer

mkfs -t xfs -c /dev/sdb

Answer

xfs_repair /dev/sdb

Question 7

A storage administrator is preparing a 4 TB USB 3.0 external drive to hold large backup archives. The drive must be usable on Linux, Windows, and macOS workstations, and single files will occasionally exceed 4 GB. Which filesystem should be created on the single partition /dev/sdb1?

Accepted Answer

mkfs.exfat /dev/sdb1. exFAT was designed for flash and removable media and is supported out of the box by modern Linux, Windows, and macOS. It also has no 4 GB per-file ceiling, unlike FAT32, so it satisfies both the cross-platform and large-file requirements. The other filesystems either impose a size limit or lack native support on one of the required operating systems.

Answer

mkfs.vfat -F 32 /dev/sdb1

Answer

mkfs.ext4 /dev/sdb1

Answer

mkfs.xfs /dev/sdb1

Question 8

A Linux server uses a software RAID1 array /dev/md0 assembled from /dev/sdb1 and /dev/sdc1. The administrator wants to replace the failing disk /dev/sdc with a new disk /dev/sdd without losing data or interrupting service. Which two steps are required to correctly replace the disk in the array? (Choose two.)

Accepted Answer

Mark /dev/sdc1 as failed with mdadm /dev/md0 --fail /dev/sdc1, then remove it with mdadm /dev/md0 --remove /dev/sdc1.. To replace a disk in a RAID1 array, the failed disk must first be marked failed and removed from the array. Then the new disk, partitioned identically, is added with mdadm --add, which triggers a rebuild. These two steps maintain data integrity and restore redundancy without recreating or resizing the array.

Answer

Recreate the array with mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdd1.

Answer

Run mdadm --grow /dev/md0 --raid-devices=2 to resize the array after adding the new disk.

Answer

Use dmsetup remove /dev/md0 to detach the array, then re-add the new disk.

Question 9

An administrator manages a server whose /home directory resides on the logical volume /dev/vg_users/lv_home. Usage reports show the LV is 98% full, and the volume group vg_users has 40 GB of free extents. The filesystem is ext4. Which sequence correctly expands the usable space to /home?

Accepted Answer

lvextend -L +20G /dev/vg_users/lv_home && resize2fs /dev/vg_users/lv_home. Extending an ext4 filesystem on LVM requires enlarging the logical volume first with lvextend, then expanding the filesystem with resize2fs. The volume group already has free extents, so no additional physical volume is needed. The filesystem can be resized online while /home remains mounted.

Answer

resize2fs /dev/vg_users/lv_home 20G && lvextend -L +20G /dev/vg_users/lv_home

Answer

lvextend -L +20G /dev/vg_users/lv_home && xfs_growfs /home

Answer

vgextend vg_users /dev/vg_users/lv_home && resize2fs /dev/vg_users/lv_home

Question 10

A junior administrator needs to identify the filesystem type of the device /dev/nvme0n1p2 on a running Linux server without mounting it or modifying any metadata. Which command should be used?

Accepted Answer

blkid /dev/nvme0n1p2. blkid reads filesystem superblocks and reports the type without mounting or altering the device, making it the safest and most direct way to identify the filesystem on /dev/nvme0n1p2. fdisk shows partition-table type codes rather than real filesystem metadata, mounting is unnecessarily invasive, and lsblk -f is a broader listing that is less targeted for a single-device query.

Answer

lsblk -f

Answer

mount /dev/nvme0n1p2 /mnt

Answer

fdisk -l /dev/nvme0n1p2

Question 11

A Linux server uses LVM. The volume group vg_data has 10 GB of free extents. The logical volume /dev/vg_data/lv_app is 20 GB and must be increased by 5 GB while it is mounted and actively used by an application. Which command sequence correctly extends the logical volume and then grows the ext4 filesystem online?

Accepted Answer

lvextend -L +5G /dev/vg_data/lv_app && resize2fs /dev/vg_data/lv_app. To extend an ext4 filesystem on LVM online, you first increase the logical volume with lvextend, then expand the filesystem with resize2fs. ext4 supports online growth, so the application can continue running. Using xfs_growfs on ext4 or running a filesystem check instead of resize2fs will not achieve the desired result.

Answer

lvextend -L +5G /dev/vg_data/lv_app && xfs_growfs /dev/vg_data/lv_app

Answer

lvresize -L +5G /dev/vg_data/lv_app && resize2fs /dev/vg_data/lv_app

Answer

lvextend -L 25G /dev/vg_data/lv_app && e2fsck -f /dev/vg_data/lv_app

Question 12

An administrator has a volume group vg_data with 50 GB of free extents. The logical volume /dev/vg_data/lv_archive is 200 GB and must grow to 350 GB. The administrator runs lvextend -L +150G /dev/vg_data/lv_archive and it fails. Which is the most likely cause?

Accepted Answer

The volume group does not have enough free extents to satisfy the 150 GB request.. lvextend allocates physical extents from the volume group's free pool. With only 50 GB free, a 150 GB growth request cannot be met, so the command exits with an error before touching the logical volume. The fix is to add capacity to vg_data, for example by creating a physical volume on a new disk and running vgextend, then repeating the lvextend.

Answer

The logical volume is formatted with XFS, which cannot be extended with lvextend.

Answer

The +150G syntax is invalid and should be --size 150G instead.

Answer

The filesystem must be unmounted before any logical volume can be extended.

Question 13

A junior administrator needs to mount an ISO image located at /opt/install.iso to the /mnt/iso directory to access its contents. Which command accomplishes this?

Accepted Answer

mount -o loop /opt/install.iso /mnt/iso. Mounting an ISO file requires the loop option so that the kernel treats the file as a block device. The command mount -o loop /opt/install.iso /mnt/iso creates a loop device automatically and mounts the ISO9660 filesystem, making the contents accessible. This is the standard method for accessing ISO images without burning them.

Answer

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

Answer

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

Answer

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

Question 14

An administrator needs to add a new 8 GB swap area on a server that already has a 2 GB swap partition. The system has free space in the volume group vg_sys. Which command creates a logical volume named lv_swap of exactly 8 GB and prepares it for swap use?

Accepted Answer

lvcreate -L 8G -n lv_swap vg_sys && mkswap /dev/vg_sys/lv_swap && swapon /dev/vg_sys/lv_swap. The correct procedure is to create the logical volume with lvcreate -L 8G -n lv_swap vg_sys, initialize it with mkswap, and activate it with swapon. The -L option specifies an absolute size in gigabytes, which matches the 8 GB requirement. Persistent activation requires an /etc/fstab entry, but the immediate creation and activation sequence is as shown.

Answer

vgcreate -L 8G -n lv_swap vg_sys && mkswap /dev/vg_sys/lv_swap && swapon /dev/vg_sys/lv_swap

Answer

lvcreate -L 8G -n lv_swap vg_sys && mkfs.swap /dev/vg_sys/lv_swap && swapon /dev/vg_sys/lv_swap

Answer

lvcreate -l 8 -n lv_swap vg_sys && mkswap /dev/vg_sys/lv_swap && swapon -a

Question 15

A Linux server has a volume group named vg_data that currently contains two physical volumes. The administrator needs to remove /dev/sdb1 from vg_data, but pvremove /dev/sdb1 returns an error stating the physical volume is still in use. Which command should the administrator run FIRST to migrate the extents off /dev/sdb1 onto the remaining physical volume?

Accepted Answer

pvmove /dev/sdb1. To safely remove a physical volume from an active volume group, the allocated extents must first be moved to other PVs. pvmove performs this online migration without unmounting filesystems. Only after the PV reports zero used extents can vgreduce detach it and pvremove clear its label. Attempting vgreduce or pvremove beforehand fails because LVM protects allocated data.

Answer

lvconvert --repair vg_data

Answer

vgreduce vg_data /dev/sdb1

Answer

pvremove /dev/sdb1 --force