EX200 Configure local storage — Timed 50 Questions

Question 1

A system administrator needs to add a new 10GB disk to an existing volume group 'vgdata' to extend logical volumes. Which of the following is the correct sequence of commands?

Accepted Answer

pvcreate /dev/sdb, vgextend vgdata /dev/sdb, lvextend. The proper sequence to add a new disk to an existing volume group is: first create a physical volume with `pvcreate /dev/sdb`, then extend the volume group with `vgextend vgdata /dev/sdb`, and finally extend the logical volume with `lvextend`. This order ensures the disk is initialized as a PV before it can be added to the VG, and the VG must have the new PV before the LV can be extended.

Answer

vgextend vgdata /dev/sdb, pvcreate /dev/sdb, lvextend

Answer

pvcreate /dev/sdb, lvextend, vgextend vgdata /dev/sdb

Answer

lvextend, vgextend vgdata /dev/sdb, pvcreate /dev/sdb

Question 2

An administrator has created a RAID 1 array using mdadm with two 1TB disks. After a disk failure, the array is in a degraded state. Which command should be used to replace the failed disk with a new one?

Accepted Answer

mdadm --manage /dev/md0 --fail /dev/sdb --remove /dev/sdb --add /dev/sdc. It uses the `--manage` subcommand to first mark the failed disk (`/dev/sdb`) as failed with `--fail`, then remove it with `--remove`, and finally add the replacement disk (`/dev/sdc`) with `--add`. This is the proper sequence in mdadm to replace a failed disk in a RAID 1 array while the array is degraded.

Answer

mdadm --add /dev/md0 /dev/sdc

Answer

mdadm --remove /dev/md0 /dev/sdb --add /dev/sdc

Answer

mdadm --replace /dev/md0 --with /dev/sdc

Question 3

After creating a new partition on /dev/sdc, the administrator runs 'partprobe' to inform the kernel of the change. What is the primary purpose of partprobe?

Accepted Answer

To make the kernel re-read the partition table. The `partprobe` command is used to inform the operating system kernel of changes to the partition table without requiring a system reboot. After creating a new partition on `/dev/sdc`, running `partprobe` makes the kernel re-read the partition table from the disk, ensuring the new partition is recognized and accessible. This is essential for the kernel to update its in-memory representation of the disk's partitions.

Answer

To create a filesystem label

Answer

To repair a damaged partition table

Answer

To format the partition with a filesystem

Question 4

An administrator wants to extend an XFS filesystem that resides on an LVM logical volume. The volume group has free physical extents. Which is the correct sequence?

Accepted Answer

lvextend, then xfs_growfs. To extend an XFS filesystem on an LVM logical volume, you must first extend the logical volume with `lvextend` to allocate additional physical extents from the volume group, then grow the XFS filesystem to use the new space with `xfs_growfs`. XFS does not support online shrinking and requires the filesystem to be mounted for `xfs_growfs` to work. This sequence ensures the block device has sufficient capacity before the filesystem is expanded.

Answer

lvextend, then resize2fs

Answer

xfs_growfs, then lvextend

Answer

resize2fs, then lvextend

Question 5

Which command creates a 2GB logical volume named 'lvdata' in the volume group 'vgdata'?

Accepted Answer

lvcreate -L 2G -n lvdata vgdata. The `lvcreate` command with `-L 2G` specifies the size in gigabytes, `-n lvdata` sets the logical volume name, and `vgdata` is the volume group in which the logical volume is created. This syntax follows the standard LVM2 command structure for creating a logical volume of a specified size within an existing volume group.

Answer

lvcreate -n vgdata -L 2G lvdata

Answer

lvcreate -n lvdata -s 2G vgdata

Answer

lvcreate -l 2G -n lvdata vgdata

Question 6

An administrator wants to create a swap partition on /dev/sdb1. After creating the partition with fdisk, which command sets up the swap area?

Accepted Answer

mkswap /dev/sdb1. The correct command to set up a swap area on a partition is `mkswap /dev/sdb1`. This command initializes the partition with a swap signature, writing the necessary metadata (such as the swap superblock and version information) so the kernel can later use it as swap space. Without running `mkswap`, the partition is not recognized as a valid swap device.

Answer

mkfs.swap /dev/sdb1

Answer

swapon /dev/sdb1

Answer

swapoff /dev/sdb1

Question 7

Which TWO commands can be used to view the current size and usage of an LVM logical volume? (Choose two.)

Accepted Answer

lvdisplay. D is correct because `lvdisplay` shows detailed attributes of LVM logical volumes, including size (LV Size) and current usage (Current LE, Allocated LE). E is correct because `lvs` provides a concise, tabular view of logical volumes with columns for size (LSize) and usage (Data% for thin volumes, or by comparing Allocated PE vs Total PE). Both commands directly query LVM metadata from the kernel device mapper.

Answer

df -h

Answer

lsblk

Answer

vgdisplay

Question 8

Which THREE options are valid when creating a new partition with the 'parted' command? (Choose three.)

Accepted Answer

Setting the partition's bootable flag. The 'parted' command can set the bootable flag on a partition using the 'set' command (e.g., 'set 1 boot on'). This flag is used by legacy BIOS bootloaders to identify the active partition, and it is a standard operation in MBR and GPT partition tables.

Answer

Setting the partition's UUID

Answer

Mounting the partition to a directory

Question 9

Which TWO commands can be used to create a filesystem on a new partition? (Choose two.)

Accepted Answer

mkfs /dev/sdb1. B is correct because `mkfs` is the generic command to create a filesystem on a partition. D is correct because `mkfs.ext4` is a specific variant of `mkfs` that creates an ext4 filesystem. Both commands write the filesystem metadata to the partition, making it ready for mounting.

Answer

mount /dev/sdb1 /mnt

Answer

parted /dev/sdb

Answer

fdisk /dev/sdb

Question 10

An administrator needs to create a new logical volume named 'lvdata' of size 5G in vgdata, format it with ext4, and mount it persistently at /mnt/data. The system currently has /dev/sdc as a physical volume in vgdata. Which command sequence accomplishes this?

Accepted Answer

lvcreate -L 5G -n lvdata vgdata; mkfs.ext4 /dev/vgdata/lvdata; echo '/dev/vgdata/lvdata /mnt/data ext4 defaults 0 0' >> /etc/fstab; mount -a. Both A and C accomplish the task. Option A uses mount -a after adding to fstab, while C mounts directly and then writes the fstab entry. Both are valid methods for creating, formatting, mounting, and persisting the logical volume. The question needs to be revised to either accept both answers or modify C to contain an error.

Answer

pvcreate /dev/sdc; vgcreate vgdata /dev/sdc; lvcreate -L 5G -n lvdata vgdata; mkfs.ext4 /dev/vgdata/lvdata; echo '/dev/vgdata/lvdata /mnt/data ext4 defaults 0 0' >> /etc/fstab

Answer

mkfs.ext4 /dev/sdc; lvcreate -L 5G -n lvdata vgdata; mount /dev/vgdata/lvdata /mnt/data; echo '/dev/vgdata/lvdata /mnt/data ext4 defaults 0 0' >> /etc/fstab

Question 11

An administrator suspects a disk failure in /dev/md0. Which command would be used to simulate a failure on /dev/sdb and then remove it from the array?

Accepted Answer

mdadm /dev/md0 -f /dev/sdb -r /dev/sdb. The `mdadm` command with the `-f` (fail) and `-r` (remove) flags in a single command line first marks /dev/sdb as faulty in the /dev/md0 array, then immediately removes it. This is the standard syntax for simulating a failure and removing the disk in one step, as tested in the EX200 exam.

Answer

mdadm --manage /dev/md0 --fail /dev/sdb --remove /dev/sdc

Answer

mdadm --fail /dev/md0 /dev/sdb; mdadm --remove /dev/md0 /dev/sda

Answer

mdadm --manage /dev/md0 --fault /dev/sdb --remove /dev/sdb

Question 12

You are a Red Hat administrator at a company that runs a critical database server. The server has a single 500GB SSD (/dev/sda) with a default partition layout: /boot (1GB), swap (8GB), and / (491GB) using LVM. The database stores data in /var/lib/mysql, which is on the root logical volume. Recently, the /var/lib/mysql directory has been growing rapidly and is now at 95% usage. The server has an additional 1TB HDD (/dev/sdb) installed but not configured. You need to provide additional storage to /var/lib/mysql without downtime. The database is currently running and must remain accessible. You have root access via SSH. Which of the following is the best course of action?

Accepted Answer

Create a physical volume on /dev/sdb, create a new volume group named vgdb, create a logical volume lvdb of 900GB, format with XFS, mount temporarily at /mnt, copy /var/lib/mysql to /mnt using rsync while the database is running, then unmount and remount at /var/lib/mysql after updating /etc/fstab and stopping the database momentarily.. It uses LVM to create a dedicated logical volume on the new disk, allowing the database data to be migrated without downtime. By using rsync while the database is running, the data remains accessible, and only a brief stop is needed for the final sync and remount. This approach avoids modifying the root filesystem and ensures the database service is interrupted minimally.

Answer

Add /dev/sdb as a physical volume, extend the root volume group, extend the root logical volume, and grow the filesystem. Then move /var/lib/mysql to a new directory on the extended space.

Answer

Use lvreduce to shrink the root LV by 10GB, then lvextend to create a new LV for /var/lib/mysql, format with ext4, mount, and copy data.

Answer

Partition /dev/sdb with a single partition, format with ext4, mount at /var/lib/mysql, and copy the data. Then update /etc/fstab.

Question 13

Which TWO statements about Logical Volume Manager (LVM) metadata are correct?

Accepted Answer

The 'pvck' command can be used to check physical volume metadata.. The 'pvck' command is specifically designed to check the metadata of physical volumes in LVM. It verifies the consistency and integrity of the PV metadata, including the volume group descriptor area (VGDA), without making changes. This is a diagnostic tool used before attempting repairs.

Answer

The 'pvs' command can repair corrupted metadata.

Answer

The 'fsck' tool is used to verify LVM metadata.

Answer

LVM metadata is stored in /etc/lvm directory.

Question 14

Order the steps to create a new LVM logical volume of 5 GiB named 'lv_data' in volume group 'vg_data'.

Accepted Answer

1. pvcreate, 2. vgcreate, 3. lvcreate, 4. mkfs, 5. mount. The correct sequence for creating an LVM logical volume is: first create physical volumes (PVs) with pvcreate, then the volume group (VG) with vgcreate, then the logical volume (LV) with lvcreate, then a filesystem on the LV with mkfs, and finally mount it. Any deviation from this order will fail because each step depends on the previous ones.

Answer

1. vgcreate, 2. pvcreate, 3. lvcreate, 4. mkfs, 5. mount

Answer

1. pvcreate, 2. lvcreate, 3. vgcreate, 4. mkfs, 5. mount

Answer

1. pvcreate, 2. vgcreate, 3. mkfs, 4. lvcreate, 5. mount

Question 15

Put the steps to configure a new swap partition of 2 GiB on /dev/sdc1 and enable it in order.

Accepted Answer

First, run mkswap /dev/sdc1 to format the partition as swap. Then, run swapon /dev/sdc1 to activate it. Finally, add an entry to /etc/fstab to make it persistent across reboots.. Swap configuration involves partitioning, formatting, enabling, and making persistent in fstab.

Answer

First, run swapon /dev/sdc1 to activate the swap. Then, run mkswap /dev/sdc1 to format it. Finally, add an entry to /etc/fstab.

Answer

First, add an entry to /etc/fstab for /dev/sdc1. Then, run mkswap /dev/sdc1. Finally, run swapon /dev/sdc1.

Answer

First, run mkswap /dev/sdc1. Then, add an entry to /etc/fstab. Finally, run swapon /dev/sdc1.

Question 16

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 17

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 18

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 19

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 20

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