EX200 Configure local storage — 10 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. Option A is correct because 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. Option B is correct because 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

An administrator needs to ensure that a specific LVM logical volume is automatically mounted at boot with the 'noexec' option. Which configuration file and entry should be used?

Accepted Answer

/etc/fstab: /dev/vg/lv /mnt ext4 defaults,noexec 0 0. Option C is correct because /etc/fstab is the standard configuration file for defining filesystem mount points and options that are applied automatically at boot. The entry specifies the logical volume device, mount point, filesystem type, and mount options including 'noexec' to prevent execution of binaries on that filesystem. The 'defaults' keyword ensures standard mount behavior is applied before the 'noexec' option overrides the exec permission.

Answer

/etc/fstab: /dev/vg/lv /mnt ext4 noexec 0 0

Answer

/etc/rc.d/rc.local: mount /dev/vg/lv /mnt -o noexec

Answer

/etc/rc.local: mount -o noexec /dev/vg/lv /mnt

Question 4

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 5

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 6

A server has a software RAID 5 array /dev/md0. One of its disks fails. The administrator wants to replace it without rebooting. Which command should be used to mark the disk as failed?

Accepted Answer

mdadm --fail /dev/md0 /dev/sdb. The correct command to mark a disk as failed in a software RAID array without rebooting is `mdadm --fail /dev/md0 /dev/sdb`. This command tells the md driver to mark the specified disk as faulty, which triggers the RAID 5 array to degrade and allows the failed disk to be removed and replaced while the system remains online.

Answer

mdadm --fault /dev/md0 /dev/sdb

Answer

echo faulty > /sys/block/md0/md/dev-sdb/state

Answer

mdadm --set-faulty /dev/md0 /dev/sdb

Question 7

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

Accepted Answer

lvcreate -L 2G -n lvdata vgdata. Option A is correct because 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 8

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 9

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 10

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

Accepted Answer

Setting the partition's bootable flag. Option B is correct because 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