LFCS Storage Management Practice Test 5 — 15 Questions

Question 1

Refer to the exhibit. The administrator wants to create a RAID 1 array using /dev/sdb1 and /dev/sdc1. Which command should be used?

Accepted Answer

mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1. RAID 1 (mirroring) requires exactly two devices to provide redundancy by duplicating data across both disks. The `--level=1` parameter specifies RAID 1, and `--raid-devices=2` matches the two partitions /dev/sdb1 and /dev/sdc1.

Answer

mdadm --create /dev/md0 --level=5 --raid-devices=2 /dev/sdb1 /dev/sdc1

Answer

mdadm --create /dev/md0 --level=10 --raid-devices=2 /dev/sdb1 /dev/sdc1

Answer

mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1

Question 2

Order the steps to configure a cron job that runs a script every day at 2 AM.

Accepted Answer

Step 1: Run 'crontab -e' to open the crontab editor.
Step 2: Add the line '0 2 * * * /path/to/script'.
Step 3: Save and exit the editor.
Step 4: Run 'crontab -l' to verify the job is scheduled.. The correct order to configure a cron job is: open the crontab file with 'crontab -e', add the cron expression with the correct time fields (minute, hour, day, month, weekday) and the script path, save the file, and then verify with 'crontab -l'. Common mistakes include adding the line before opening the editor, saving before adding, or verifying before editing.

Answer

Step 1: Add the line '0 2 * * * /path/to/script' directly to the crontab.
Step 2: Run 'crontab -e' to open the editor.
Step 3: Save and exit the editor.
Step 4: Run 'crontab -l' to verify.

Answer

Step 1: Run 'crontab -e' to open the editor.
Step 2: Save and exit the editor immediately.
Step 3: Add the line '0 2 * * * /path/to/script'.
Step 4: Run 'crontab -l' to verify.

Answer

Step 1: Run 'crontab -l' to verify existing jobs.
Step 2: Run 'crontab -e' to open the editor.
Step 3: Add the line '0 2 * * * /path/to/script'.
Step 4: Save and exit.

Question 3

Match each Linux package management command to its distribution.

Accepted Answer

apt: Debian/Ubuntu. Package managers are tied to specific distribution families: apt (Debian/Ubuntu), yum (RHEL/CentOS 7), dnf (Fedora/RHEL 8+), pacman (Arch), and zypper (openSUSE). Common confusions arise from mixing these tools across distributions.

Answer

apt: Red Hat Enterprise Linux

Answer

yum: Debian

Question 4

An administrator wants to see the disk usage of the /var directory in a human-readable format. Which command should be used?

Accepted Answer

du -sh /var. The `du -sh /var` command is correct because `du` (disk usage) estimates file and directory space usage, and the `-s` flag summarizes the total for `/var` while `-h` provides human-readable output (e.g., KiB, MiB, GiB). This directly shows the disk space consumed by the `/var` directory and its contents.

Answer

df -h /var

Answer

fdisk -l /var

Answer

ls -lh /var

Question 5

An administrator has created an LVM thin pool. Which command should be used to create a thin logical volume named 'thinvol' of size 100GB from the thin pool 'pool1' in volume group 'vg1'?

Accepted Answer

lvcreate -V 100G -T vg1/pool1 --name thinvol. The `lvcreate` command for thin logical volumes requires the `-V` flag to specify the virtual size of the thin volume and the `-T` flag to reference the thin pool. The syntax `-V 100G -T vg1/pool1 --name thinvol` correctly creates a thin logical volume named 'thinvol' with a virtual size of 100GB from the thin pool 'pool1' in volume group 'vg1'.

Answer

lvcreate -L 100G -n thinvol vg1

Answer

lvcreate -s vg1/pool1 -n thinvol

Answer

lvcreate -L 100G -T vg1/pool1 --name thinvol

Question 6

An administrator needs to configure software RAID 5 on three disks /dev/sda, /dev/sdb, /dev/sdc with a spare disk /dev/sdd. Which command correctly creates the RAID array?

Accepted Answer

mdadm --create /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sda /dev/sdb /dev/sdc /dev/sdd. It uses the `--spare-devices=1` flag to designate `/dev/sdd` as a hot spare, while `--raid-devices=3` specifies that only three disks form the active RAID 5 array. The spare disk is listed after the active disks, which is the correct syntax for `mdadm --create`.

Answer

mdadm --create /dev/md0 --level=5 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

Answer

mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/sda /dev/sdb /dev/sdc

Answer

mdadm --create /dev/md0 --level=5 --raid-devices=3 --spare-devices=1 /dev/sda /dev/sdb /dev/sdc --spare /dev/sdd

Question 7

An administrator needs to set the reserved block percentage on an ext4 filesystem to 1% for a non-root filesystem. Which command accomplishes this?

Accepted Answer

tune2fs -m 1 /dev/sdb1. The `tune2fs -m` command sets the reserved block percentage for an ext4 filesystem, and `-m 1` sets it to exactly 1%. This is the standard way to adjust reserved space on a non-root ext4 filesystem, as root filesystems typically have a default of 5% reserved for system processes.

Answer

tune2fs -m 0.5 /dev/sdb1

Answer

tune2fs -r 1% /dev/sdb1

Answer

tune2fs -c 1 /dev/sdb1

Question 8

An admin notices a PV in a VG has failed. The VG is still accessible with redundancy. Which command sequence should be used to replace the faulty PV with a new one (/dev/sde) while the VG is active and without data loss?

Accepted Answer

pvcreate /dev/sde; vgextend VG_name /dev/sde; pvmove /dev/sdb /dev/sde; vgreduce VG_name /dev/sdb. It first creates the new PV on /dev/sde, extends the VG to include it, then uses pvmove to migrate data from the failing PV (/dev/sdb) to the new PV while the VG is active, and finally removes the faulty PV from the VG with vgreduce. This sequence ensures no data loss and maintains VG availability throughout the replacement process.

Answer

pvcreate /dev/sde; vgreduce VG_name /dev/sdb; vgextend VG_name /dev/sde; pvmove /dev/sdb

Answer

pvcreate /dev/sde; pvmove /dev/sdb /dev/sde; vgextend VG_name /dev/sde; vgreduce VG_name /dev/sdb

Answer

vgreduce --removemissing VG_name; pvcreate /dev/sde; vgextend VG_name /dev/sde; pvmove /dev/sde

Question 9

A storage administrator wants to create a software RAID 10 (1+0) array using six disks. Which mdadm command is appropriate?

Accepted Answer

mdadm --create /dev/md0 --level=10 --raid-devices=6 /dev/sd[abcdef]. It uses the proper mdadm syntax to create a RAID 10 array with six disks. The --level=10 specifies RAID 10 (a striped mirror set), and --raid-devices=6 matches the number of disks provided via the /dev/sd[abcdef] glob, which expands to /dev/sda through /dev/sdf. This command correctly creates a RAID 10 array that combines striping and mirroring across all six devices.

Answer

mdadm --create /dev/md0 --level=10 --raid-devices=6 /dev/sda /dev/sdb /dev/sdc

Answer

mdadm --create /dev/md0 --level=1 --raid-devices=6 --chunk=64 /dev/sd[abcdef]

Answer

mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

Question 10

A system administrator needs to identify all available block devices on a Linux server. Which two commands can be used to accomplish this? (Choose two.)

Accepted Answer

lsblk. lsblk (C) is correct because it reads /sys/block and udev data to list all block devices in a tree view, showing disks, partitions, and their sizes, types, and mountpoints regardless of whether they are mounted. fdisk -l (E) is correct because it enumerates every block device in /proc/partitions and prints the partition table of each disk, making it a standard way to discover all available block devices. blkid (A) only reports devices that already have a filesystem or swap signature and their UUID/LABEL, so it misses unformatted or otherwise unrecognized block devices. mount (B) shows only currently mounted filesystems, not all block devices. df -h (D) reports disk space usage of mounted filesystems only, so it also fails to reveal unmounted or unformatted block devices.

Answer

blkid

Answer

mount

Answer

df -h

Question 11

An administrator is configuring LVM and wants to display information about physical volumes, volume groups, and logical volumes. Which two commands provide this information? (Choose two.)

Accepted Answer

pvdisplay, vgdisplay, lvdisplay. Option D is correct because pvdisplay, vgdisplay, and lvdisplay are the LVM reporting commands that print detailed information about physical volumes, volume groups, and logical volumes respectively, including attributes such as size, UUID, PE size, and allocation policy. Option E is also correct because pvs, vgs, and lvs are the LVM reporting commands that produce concise, column-oriented summaries of physical volumes, volume groups, and logical volumes, making them ideal for quickly displaying this information. Option A is incorrect because pvscan, vgscan, and lvscan scan for and activate LVM metadata/devices rather than displaying detailed configuration information. Option B is incorrect because pvck, vgck, and lvck check and repair LVM metadata consistency, not report volume information. Option C is incorrect because pvcreate, vgcreate, and lvcreate create physical volumes, volume groups, and logical volumes rather than displaying information about them.

Answer

pvscan, vgscan, lvscan

Answer

pvck, vgck, lvck

Answer

pvcreate, vgcreate, lvcreate

Question 12

An administrator has added a new disk (/dev/sdb) to a Linux system. The disk is to be used as a physical volume in an existing volume group 'vg_data'. Which sequence of commands should be executed to make the disk available to the volume group?

Accepted Answer

pvcreate /dev/sdb; vgextend vg_data /dev/sdb. It first initializes the disk as a physical volume using `pvcreate`, which writes LVM metadata to /dev/sdb, and then extends the existing volume group 'vg_data' with `vgextend`, adding the new PV to the VG. This is the standard two-step process for adding a new disk to an existing LVM volume group.

Answer

fdisk /dev/sdb; pvcreate /dev/sdb; vgextend vg_data /dev/sdb

Answer

pvcreate /dev/sdb; vgcreate vg_data /dev/sdb

Answer

vgcreate /dev/sdb; vgextend vg_data /dev/sdb

Question 13

A system administrator is setting up a high-availability cluster using shared storage. Which filesystem is best suited for this environment where multiple nodes need simultaneous read-write access to the same filesystem?

Accepted Answer

GFS2. GFS2 (Global File System 2) is a shared-disk cluster filesystem designed for high-availability environments where multiple nodes require simultaneous read-write access to the same filesystem. It uses a distributed lock manager (DLM) to coordinate access across nodes, ensuring data consistency without requiring a single metadata server. This makes it ideal for active-active cluster configurations with shared block storage.

Answer

Btrfs

Answer

XFS

Answer

ext4

Question 14

An administrator receives a report that a specific directory /var/log is consuming too much disk space. Which command should be used to determine the total disk space used by that directory?

Accepted Answer

du -sh /var/log. The `du -sh /var/log` command calculates the total disk space used by the specified directory. The `-s` flag summarizes the total size, `-h` provides human-readable output (e.g., in KB, MB, GB), and the path `/var/log` targets the directory in question. This is the standard Linux command for determining directory disk usage.

Answer

df -h /var/log

Answer

ls -la /var/log

Answer

fdisk /var/log

Question 15

An administrator created an LVM snapshot of a logical volume to perform a backup. During the backup, the snapshot runs out of space. What will happen to the original logical volume?

Accepted Answer

The snapshot becomes invalid and must be recreated.. When an LVM snapshot runs out of space, it becomes invalid and cannot track changes made to the original logical volume during the backup. The snapshot is automatically dropped by the device-mapper, and any attempt to mount or read it will fail. The original logical volume remains fully functional and unaffected, but the snapshot must be recreated to perform a new backup.

Answer

The original volume becomes read-only.

Answer

The backup completes successfully but data may be inconsistent.

Answer

The original volume is automatically extended.