EX200 Practice Test 19 — 15 Questions

Question 1

A company policy requires that all new logical volumes be created with a physical extent size of 16 MiB to optimize performance for large sequential I/O. During the creation of a new volume group, what parameter should be used?

Accepted Answer

vgcreate -s 16M vg_data /dev/sdc1. Option E is correct because the `-s` parameter in `vgcreate` sets the physical extent (PE) size for the volume group. A PE size of 16 MiB is specified with `-s 16M`, which ensures all subsequent logical volumes in that VG use 16 MiB extents, optimizing performance for large sequential I/O by reducing metadata overhead.

Answer

vgcreate -p 16M vg_data /dev/sdc1

Answer

vgcreate -L 16M vg_data /dev/sdc1

Answer

vgcreate -e 16M vg_data /dev/sdc1

Answer

vgcreate -c 16M vg_data /dev/sdc1

Question 2

What is the default filesystem type in Red Hat Enterprise Linux 8?

Accepted Answer

XFS. In Red Hat Enterprise Linux 8, the default filesystem type is XFS. XFS is a high-performance 64-bit journaling filesystem that supports large files and filesystems, and it has been the default since RHEL 7. The Anaconda installer selects XFS by default for the root filesystem during a standard installation.

Answer

btrfs

Answer

ZFS

Answer

ext4

Question 3

A server running RHEL 9 has an LVM logical volume /dev/vg00/lvol0 formatted with XFS, mounted at /data. The administrator needs to increase the file system size from 100GB to 150GB. Which command sequence should be used?

Accepted Answer

lvextend -L +50G /dev/vg00/lvol0; xfs_growfs /data. Option D is correct because it first extends the logical volume by the exact amount needed (+50G) using lvextend, then grows the XFS filesystem to match using xfs_growfs. XFS filesystems can be grown online (no unmount required), and xfs_growfs expands the filesystem to fill the available space in the logical volume.

Answer

xfs_info /data; lvextend -L 150G /dev/vg00/lvol0

Answer

umount /data; lvextend -L +50G /dev/vg00/lvol0; mount /data; xfs_growfs /data

Answer

resize2fs /dev/vg00/lvol0

Question 4

A system administrator needs to create an XFS filesystem on /dev/sdb1 with the label 'data'. Which command should be used?

Accepted Answer

mkfs.xfs -L data /dev/sdb1. Option D is correct because the `mkfs.xfs` command creates an XFS filesystem, and the `-L` flag assigns a label to the filesystem during creation. The command `mkfs.xfs -L data /dev/sdb1` correctly creates an XFS filesystem on the specified partition with the label 'data'.

Answer

mkfs.ext4 -L data /dev/sdb1

Answer

mkfs.xfs -l data /dev/sdb1

Answer

xfs_admin -L data /dev/sdb1

Question 5

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 6

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. Option B is correct because 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 7

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 8

A Red Hat Enterprise Linux 9 server has an LVM volume group 'vg01' that contains two physical volumes: /dev/sda2 and /dev/sdb1. After a reboot, the system fails to activate the volume group. The administrator runs 'pvdisplay' and sees one physical volume as 'unknown device'. What is the most likely cause?

Accepted Answer

The LVM filter in /etc/lvm/lvm.conf is excluding /dev/sdb1. The LVM filter in /etc/lvm/lvm.conf controls which devices LVM scans during activation. If the filter excludes /dev/sdb1, LVM will not recognize that physical volume, causing the volume group to fail activation. The 'unknown device' status indicates LVM cannot access the device metadata, not that the device is missing or corrupted.

Answer

The physical volume is corrupted and needs to be restored from backup

Answer

The filesystem on the logical volume has become corrupted, preventing LVM metadata access

Answer

The UUID of the physical volume has changed due to a disk replacement

Question 9

A team wants to run a container as a non-root user inside the container for security. Which instruction should be included in the Containerfile?

Accepted Answer

USER. The USER instruction in a Containerfile (Dockerfile) sets the user name or UID to use when running the container and for any subsequent RUN, CMD, or ENTRYPOINT instructions. By default, containers run as root (UID 0), which poses a security risk. Using USER to switch to a non-root user (e.g., USER 1001) ensures the container process runs with reduced privileges, aligning with the principle of least privilege.

Answer

PODMAN_USER

Answer

ENV USER

Answer

RUN useradd

Question 10

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. Option B is correct because 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 11

A technician is configuring a new Red Hat Enterprise Linux 9 server with multiple disks. They need to create a RAID 1 array using /dev/sda and /dev/sdb for the /boot partition. Which tool can create the RAID array and enable booting from it?

Accepted Answer

Use mdadm to create a RAID1 device and install GRUB on both disks. Option A is correct because mdadm is the standard Linux tool for creating software RAID arrays, including RAID 1 (mirroring). For the /boot partition, which must be readable by the bootloader, GRUB must be installed on both disks in the RAID 1 array to ensure bootability if one disk fails. mdadm creates the RAID device, and GRUB can then be installed on each disk's MBR or GPT partition.

Answer

Use parted to create a RAID array directly by specifying the RAID level

Answer

Use fdisk to create a RAID partition and then format with ext4

Answer

Use LVM to create a mirrored logical volume for /boot

Question 12

A system has a logical volume that is thinly provisioned. The thin pool has a size of 100GB and the thin volume has a virtual size of 500GB. The administrator notices that the thin pool has only 5GB of data written so far. Which command will display the current data usage of the thin volume?

Accepted Answer

lvs -o lv_name,data_percent. Option D is correct because the `lvs -o lv_name,data_percent` command specifically displays the percentage of the thin pool that has been consumed by the thinly provisioned logical volume. For thin volumes, the `data_percent` field reports the actual data usage relative to the thin pool's capacity, which is exactly what the administrator needs to see the current 5GB usage against the 100GB pool.

Answer

df -h /dev/mapper/vg01-thinvol

Answer

lsblk /dev/mapper/vg01-thinvol

Answer

lvdisplay /dev/vg01/thinvol

Question 13

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. Option B is correct because 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 14

A database server experiences high disk I/O wait times. The administrator runs 'iostat -x 1' and sees that the avgqu-sz for /dev/sda is 25 and await is 200 ms. The disk is a single 7200 RPM SATA drive. Which action is most likely to improve performance?

Accepted Answer

Replace the drive with an SSD or add additional drives in RAID 10. The high avgqu-sz (25) and await (200 ms) indicate the single 7200 RPM SATA drive is saturated, as its maximum IOPS is typically around 75-100 random I/O operations per second. Replacing it with an SSD (which can handle thousands of IOPS) or adding drives in RAID 10 (which increases IOPS through parallelism) directly addresses the hardware bottleneck. No software tuning can overcome the physical limitations of a single spinning disk under heavy I/O load.

Answer

Increase the read-ahead buffer using blockdev --setra

Answer

Change the I/O scheduler from CFQ to noop

Answer

Run 'fsck -f' on the filesystem to check for fragmentation

Question 15

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