EX200 Configure local storage Practice Test 4 — 15 Questions

Question 1

Which TWO of the following are required steps when migrating a logical volume from one physical volume to another in the same volume group?

Accepted Answer

Remove the source physical volume from the volume group with vgreduce after migration. After using pvmove to relocate all physical extents from the source physical volume to the target, you must remove the source PV from the volume group using vgreduce to clean up the volume group metadata and free the device for other use. This step ensures the volume group no longer references the now-empty source PV.

Answer

Delete and recreate the logical volume on the new physical volume

Answer

Add the new physical volume to the volume group with vgextend if not already present

Answer

Extend the logical volume to include the new physical volume

Question 2

Which THREE of the following are valid utilities for creating partitions on a disk in Red Hat Enterprise Linux?

Accepted Answer

fdisk. C is correct because `fdisk` is a traditional command-line utility for creating, deleting, and managing MBR (Master Boot Record) partition tables on disks in Red Hat Enterprise Linux. It supports interactive and scripted partitioning, making it a valid tool for local storage configuration.

Answer

mkfs

Answer

mount

Question 3

The /data filesystem is at 99% capacity. The LVM setup shows that the volume group has 50GB free space, but the logical volume is only 100GB. What is the correct sequence of commands to increase the filesystem to use all available space in the volume group?

Accepted Answer

lvextend -L +50G /dev/mapper/vg01-data && xfs_growfs /data. The volume group has 50GB free space, so you need to extend the logical volume by +50GB (not to 50GB) using `lvextend -L +50G`, and then grow the XFS filesystem with `xfs_growfs /data` (the mount point, not the block device). The `+` sign indicates an addition to the current size, while omitting it would set an absolute size.

Answer

lvextend -L 50G /dev/mapper/vg01-data && xfs_growfs /dev/mapper/vg01-data

Answer

lvextend -L +50G /dev/mapper/vg01-data && resize2fs /dev/mapper/vg01-data

Answer

xfs_growfs /dev/mapper/vg01-data && lvextend -L +50G /dev/mapper/vg01-data

Question 4

An administrator needs to add a new 20GB disk /dev/sdb to a RHEL 9 server and mount it permanently at /data. The disk is unpartitioned. Which sequence of commands correctly accomplishes this?

Accepted Answer

fdisk /dev/sdb → mkfs.ext4 /dev/sdb1 → echo '/dev/sdb1 /data ext4 defaults 0 0' >> /etc/fstab → mount -a. It follows the proper sequence for adding a new unpartitioned disk: create a partition with fdisk, format the partition with mkfs.ext4, add an entry to /etc/fstab for permanent mounting, and then use mount -a to mount all filesystems from fstab. This ensures the disk is mounted persistently across reboots, which is required by the question.

Answer

fdisk /dev/sdb → mkfs.ext4 /dev/sdb1 → mount /dev/sdb1 /data

Answer

mkfs.ext4 /dev/sdb → mount /dev/sdb /data

Answer

parted /dev/sdb → mkfs.ext4 /dev/sdb1 → mount /dev/sdb1 /data

Question 5

A volume group vg_data has no free extents. An admin adds a new disk /dev/sdc and wants to extend the logical volume lv_data (ext4 filesystem) by 5GB. Which sequence of commands is correct?

Accepted Answer

pvcreate /dev/sdc → vgextend vg_data /dev/sdc → lvextend -L+5G /dev/vg_data/lv_data → resize2fs /dev/vg_data/lv_data. It follows the proper sequence: first create the physical volume with pvcreate, then extend the volume group with vgextend, then extend the logical volume with lvextend, and finally resize the ext4 filesystem with resize2fs. Since the filesystem is ext4, the resize2fs command is required after lvextend to make the additional space available to the filesystem.

Answer

pvcreate /dev/sdc → vgextend vg_data /dev/sdc → lvextend -L+5G /dev/vg_data/lv_data

Answer

lvextend -L+5G /dev/vg_data/lv_data → pvcreate /dev/sdc → vgextend vg_data /dev/sdc

Answer

fdisk /dev/sdc → mkfs.ext4 /dev/sdc1 → pvcreate /dev/sdc1 → vgextend vg_data /dev/sdc1 → lvextend -L+5G /dev/vg_data/lv_data

Question 6

A system fails to mount an XFS filesystem at boot. The /etc/fstab entry is: UUID=abc123 /mnt xfs defaults 0 0. Running mount -a shows: 'mount: wrong fs type, bad option, bad superblock on /dev/sdb1'. Which is the most likely cause?

Accepted Answer

The filesystem on /dev/sdb1 is not XFS but ext4.. The error 'wrong fs type, bad option, bad superblock' occurs when the device exists but the filesystem type does not match or the superblock is unreadable. Since the error explicitly mentions /dev/sdb1, the UUID must have resolved to that device. Therefore, a UUID mismatch would produce a different error like 'can't find UUID=abc123' or 'no such device'. The most likely cause is that /dev/sdb1 is not formatted as XFS (e.g., it is ext4). A missing mount point gives 'No such file or directory', and kernel XFS support issues typically produce 'unknown filesystem type'.

Answer

The UUID specified in fstab does not match the actual UUID of /dev/sdb1.

Answer

The mount point /mnt does not exist.

Answer

The kernel does not have XFS support enabled.

Question 7

Which single command shows the UUID of a filesystem on /dev/sdb1?

Accepted Answer

blkid /dev/sdb1. The `blkid /dev/sdb1` command queries the libblkid library to read the filesystem metadata directly from the block device, displaying attributes including the UUID (Universally Unique Identifier) stored in the superblock. This is the standard, single-purpose command to retrieve the UUID of a specific partition.

Answer

df -h

Answer

mount

Answer

fdisk -l

Question 8

Which TWO commands can be used to create a physical volume for LVM? (Choose exactly two.)

Accepted Answer

pvcreate /dev/sdb1. The `pvcreate` command initializes a block device (such as a partition or an entire disk) for use as a physical volume in LVM. Option B targets a partition `/dev/sdb1`, and option C targets the whole disk `/dev/sdb` — both are valid devices that can be initialized as physical volumes, as LVM can operate on either.

Answer

mkfs.ext4

Answer

lvcreate

Answer

vgcreate

Question 9

Which THREE filesystem types are natively supported in RHEL 8/9 for local storage? (Choose exactly three.)

Accepted Answer

vfat. A is correct because vfat (FAT32) is natively supported in RHEL 8/9 for local storage, primarily for compatibility with UEFI boot partitions and removable media. The kernel includes the vfat module, and mkfs.vfat is available from the dosfstools package, allowing creation and mounting of FAT32 filesystems without additional software.

Answer

ntfs

Answer

btrfs

Question 10

Which TWO commands can be used to list block devices and their attributes? (Choose exactly two.)

Accepted Answer

lsblk. B (lsblk) is correct because it lists all block devices (e.g., /dev/sda, /dev/nvme0n1) and displays their attributes such as size, type, mount point, and model in a tree-like format by reading the sysfs filesystem. E (blkid) is correct because it shows block device attributes like UUID, filesystem type, and LABEL by querying the libblkid library, which reads metadata directly from the device.

Answer

fdisk -l

Answer

du

Answer

df

Question 11

A junior admin receives a ticket: 'The /var partition is filling up quickly. The server has an extra 100GB disk /dev/sdb. The /var filesystem is on logical volume lv_var in volume group vg_system. Currently, vg_system has no free extents. The admin's plan: create a new physical volume on /dev/sdb, extend vg_system, extend lv_var, and resize the filesystem. He runs: pvcreate /dev/sdb; vgextend vg_system /dev/sdb; lvextend -L+100G /dev/vg_system/lv_var; resize2fs /dev/vg_system/lv_var. The system reports error: 'resize2fs: Invalid argument while trying to open /dev/vg_system/lv_var'. What is the most likely mistake?

Accepted Answer

He used resize2fs instead of xfs_growfs because /var is typically XFS.. The error 'resize2fs: Invalid argument while trying to open /dev/vg_system/lv_var' indicates that the filesystem on lv_var is not ext2/3/4 but likely XFS. RHEL 8/9 defaults to XFS for /var, and XFS requires xfs_growfs (which operates on a mount point, not a block device) instead of resize2fs. Using resize2fs on an XFS filesystem produces this exact error.

Answer

He should have used lvresize instead of lvextend.

Answer

He forgot to run partprobe after pvcreate.

Answer

The lvextend command failed because vg_system has no free extents.

Question 12

A production server runs RHEL 8 with a software RAID 5 array (/dev/md0) composed of three disks: /dev/sda, /dev/sdb, /dev/sdc. The array is used to store database files. The server experiences a disk failure on /dev/sdc. The admin replaces /dev/sdc with an identical disk and wants to rebuild the array. He runs: mdadm /dev/md0 --add /dev/sdc. The command completes without error, but the array shows a degraded state after several hours. What should the admin do next?

Accepted Answer

Run mdadm --detail /dev/md0 to check the status and rebuild progress.. After adding a replacement disk to a RAID 5 array, the rebuild process begins automatically but may take hours depending on disk size and I/O load. Running `mdadm --detail /dev/md0` allows the admin to check the current state, rebuild progress (e.g., percentage complete), and any errors that might have stalled the rebuild. This is the first diagnostic step to determine if the rebuild is still ongoing, has failed, or is degraded for another reason.

Answer

Rebuild will happen automatically; just wait longer.

Answer

Recreate the array using mdadm --create with the same parameters.

Answer

Format /dev/sdc with a filesystem before adding to the array.

Question 13

A RHEL 8 system has an ext4 filesystem on /dev/sdb1 mounted at /backup. The admin runs out of space and wants to extend the filesystem. He adds a new disk /dev/sdc, creates a partition /dev/sdc1 (all space), adds it to LVM by creating a PV and extending the VG that contains the LV for /backup. He then extends the logical volume with lvextend -L+20G /dev/vg_backup/lv_backup. The command succeeds, but the filesystem still shows the old size. What did he forget to do?

Accepted Answer

Resize the filesystem using resize2fs.. When extending an LVM logical volume, the `lvextend` command only expands the logical volume's block device, not the filesystem residing on it. After extending the LV, the admin must run `resize2fs` (for ext4) to resize the filesystem to match the new LV size. Without this step, the kernel still sees the old filesystem metadata, so `df -h` reports the original size.

Answer

Reboot the system to recognize the new space.

Answer

Run lvchange -ay to activate the logical volume.

Answer

Unmount the filesystem before extending the LV.

Question 14

An admin is setting up a new RHEL 9 server. He has two disks: /dev/sda (500GB) and /dev/sdb (500GB). He wants to create a 300GB logical volume for application data, with the ability to take snapshots. He decides to use LVM thin provisioning. He creates a physical volume on /dev/sda, a volume group vg_data, and a thin pool with 300GB of data space and 10GB metadata. He then creates a thin volume lv_app of 300GB. Later, he wants to extend lv_app to 400GB as usage increases. He runs 'lvextend -L+100G /dev/vg_data/lv_app'. The command succeeds, but the application reports no additional space. What is the likely issue?

Accepted Answer

He forgot to resize the filesystem (e.g., xfs_growfs or resize2fs).. When extending a thin volume, the underlying logical volume is extended, but the filesystem on top of it does not automatically grow. The admin must run a filesystem-specific command like xfs_growfs (for XFS) or resize2fs (for ext4) to make the additional space available to the application. Without this step, the filesystem remains at its original size, so the application sees no change.

Answer

The thin pool has insufficient free space to accommodate the extension.

Answer

The thin volume must be unmounted to extend.

Answer

He should have used lvextend with the --resizefs option.

Question 15

During a system audit, an administrator finds that a filesystem mounted at /srv/data with ext4 is not showing in /etc/fstab. Further investigation reveals that the underlying device is an LVM logical volume lv_data in vg_data. The administrator wants to ensure the filesystem is mounted at boot. He adds an entry to /etc/fstab using the device path /dev/vg_data/lv_data. On reboot, the system fails to mount the filesystem and enters emergency mode. The logical volume and filesystem are intact. What is the most likely reason for the failure?

Accepted Answer

The device path /dev/vg_data/lv_data is a symlink that may not be available; use /dev/mapper/vg_data-lv_data or UUID.. The device path /dev/vg_data/lv_data is a symbolic link created by LVM that may not be available early in the boot process because the device mapper nodes are not yet created. The correct approach is to use the stable /dev/mapper/vg_data-lv_data path or the filesystem UUID in /etc/fstab to ensure reliable mounting at boot.

Answer

The mount point /srv/data does not exist.

Answer

The filesystem type specified in fstab is incorrect.

Answer

The logical volume is not activated at boot because lvm2-lvmetad is not running.