LPIC-2 Block Devices, Filesystems and Advanced Storage Practice Test 2 — 15 Questions

Question 1

Which command can be used to create a swap partition on /dev/sdb1?

Accepted Answer

mkswap /dev/sdb1; swapon /dev/sdb1. B is correct because creating a swap partition requires two steps: first, `mkswap` initializes the partition as a swap area by writing a swap signature (UUID and superblock) to /dev/sdb1; second, `swapon` activates the swap space, making it available to the kernel for paging. Without `mkswap`, the partition lacks the necessary swap metadata and cannot be used.

Answer

swapcreate /dev/sdb1

Answer

swapon /dev/sdb1

Answer

mkfs.swap /dev/sdb1

Question 2

An administrator wants to convert an ext4 filesystem to Btrfs without losing data. Which procedure should be used?

Accepted Answer

btrfs-convert /dev/sda1. The correct procedure is to use `btrfs-convert /dev/sda1`, which is a dedicated tool that performs an in-place conversion of an existing ext2/3/4 filesystem to Btrfs while preserving all existing data. It works by creating a Btrfs filesystem that wraps the original ext4 data structures, then allowing a gradual migration to native Btrfs features via a background process.

Answer

mkfs.btrfs /dev/sda1

Answer

cp -a /mnt/ext4 /mnt/btrfs

Answer

btrfs device add /dev/sda1 /mnt

Question 3

A filesystem check on an XFS filesystem reports corruption. What is the recommended way to repair it?

Accepted Answer

Run xfs_repair -n first, then unmount and repair.. The recommended procedure for repairing a corrupted XFS filesystem is to first run `xfs_repair -n` in dry-run mode to assess the damage without making changes, then unmount the filesystem and run `xfs_repair` to perform the actual repair. XFS does not support online repair; the filesystem must be unmounted for write operations to avoid further corruption.

Answer

Run xfs_check on the mounted filesystem.

Answer

Run xfs_repair on the unmounted filesystem.

Answer

Run fsck -t xfs on the mounted filesystem.

Question 4

Which of the following is the primary configuration file for the udev device manager?

Accepted Answer

/etc/udev/udev.conf. The primary configuration file for the udev device manager is /etc/udev/udev.conf. This file sets global parameters such as the device timeout, logging priority, and the default permissions for device nodes. While custom rules are placed in /etc/udev/rules.d/, the main configuration file that controls udev's behavior is udev.conf.

Answer

/etc/udev/rules.d/

Answer

/lib/udev/rules.d/

Answer

/etc/udev/rules.d/

Question 5

An administrator wants to create a thin provisioned LVM pool and a thin volume. Which sequence of commands is correct?

Accepted Answer

lvcreate -L 10G --thinpool vg/pool; lvcreate -V 5G --thin vg/pool/thinvol. It uses the correct LVM commands to create a thin provisioned pool and a thin volume. The first command, `lvcreate -L 10G --thinpool vg/pool`, creates a thin pool named 'pool' in volume group 'vg' with a 10G metadata and data area. The second command, `lvcreate -V 5G --thin vg/pool/thinvol`, creates a thin volume named 'thinvol' within that pool, specifying the virtual size with `-V`. The `--thinpool` and `--thin` flags are the proper LVM2 syntax for thin provisioning.

Answer

lvcreate -L 10G -T vg/pool; lvcreate -V 5G -T vg/pool/thinvol

Answer

lvcreate -L 10G -T vg/pool; lvcreate -n thinvol -V 5G vg/pool

Answer

lvcreate -L 10G -T vg/pool; lvcreate -V 5G -n thinvol vg/pool

Question 6

Which TWO commands display UUIDs of block devices? (Select TWO)

Accepted Answer

lsblk -o UUID. Option B, `lsblk -o UUID`, is correct because lsblk reads the udev/sysfs device tree and can output the filesystem UUID column for each block device when the UUID column is requested with -o. Option D, `blkid`, is correct because blkid directly probes block devices and prints their UUID (and TYPE/LABEL) attributes, making it the canonical command for displaying filesystem UUIDs. Option A, `parted /dev/sda print`, shows the partition table, sizes, and partition types but not filesystem UUIDs, so it does not qualify. Option C, `udevadm info --query=all --name=/dev/sda`, dumps udev properties for the device node but does not present filesystem UUIDs in the way the question requires. Option E, `fdisk -l`, lists partition tables and disk geometry but does not display filesystem UUIDs.

Answer

parted /dev/sda print

Answer

udevadm info --query=all --name=/dev/sda

Answer

fdisk -l

Question 7

A company runs a database server on Linux with a 4-disk RAID 10 array using mdadm. The server recently experienced a power outage. After reboot, the array is not assembling automatically. The administrator runs `mdadm --assemble --scan` and it fails with a message: 'mdadm: /dev/md0 has been found but is not a valid md superblock.' The administrator checks /proc/mdstat and sees no arrays. The disks /dev/sda, /dev/sdb, /dev/sdc, /dev/sdd are present. Running `mdadm --examine /dev/sda` shows no md superblock, but the disk contains data partitions. The administrator suspects that the superblock may be corrupted or that the disks were accidentally overwritten. The administrator has documentation that the array was created with the following parameters: RAID level 10, 4 disks, chunk size 512 KiB, metadata 1.2. What is the best course of action to recover the array?

Accepted Answer

Use `mdadm --create --level=10 --raid-devices=4 --chunk=512 --metadata=1.2 --assume-clean /dev/md0 /dev/sda /dev/sdb /dev/sdc /dev/sdd` and then mount.. When the md superblock is missing or corrupted on all disks (as confirmed by `mdadm --examine` showing no superblock), the only way to recover the array is to recreate it with `--assume-clean`. This tells mdadm to trust that the data on the disks is already in a consistent RAID 10 layout without performing an initial resync, which would overwrite the existing data. The parameters must exactly match the original creation (RAID 10, 4 disks, chunk 512 KiB, metadata 1.2) to reconstruct the correct data mapping.

Answer

Use `mdadm --create --level=10 --raid-devices=4 --chunk=512 --metadata=1.2 /dev/md0 /dev/sda /dev/sdb /dev/sdc /dev/sdd` without --assume-clean and then run fsck.

Answer

Run `mdadm --examine --scan` to probe for superblocks on all disks, then attempt recovery with --super-minor or --uuid.

Answer

Use `dd` to backup each disk's first few sectors, then use a data recovery tool.

Question 8

A server running Linux with an ext4 filesystem on /dev/sda1 has experienced an unexpected power loss due to a faulty power supply. After replacing the power supply and rebooting, the system fails to mount /dev/sda1 with an error message indicating 'wrong superblock magic number' or 'superblock corrupted'. The administrator recalls that ext4 filesystems have backup superblocks created during mkfs. Using the command 'dumpe2fs /dev/sda1 | grep -i backup' is not possible because the device is not mountable. However, the administrator remembers that for this specific filesystem, a backup superblock is located at block offset 32768 based on the output of 'mke2fs -n' from the original creation. What is the correct course of action to recover the filesystem and mount it?

Accepted Answer

Run `fsck.ext4 -b 32768 /dev/sda1` to restore the superblock, then mount the filesystem.. `fsck.ext4 -b 32768` instructs the filesystem check utility to use the backup superblock located at block offset 32768, which is a known backup location for ext4 filesystems created with default settings. This allows `fsck` to read a valid superblock, repair the primary superblock, and make the filesystem mountable again without data loss.

Answer

Run `e2fsck -fy /dev/sda1` to force a filesystem check.

Answer

Run `dd if=/dev/zero of=/dev/sda1 bs=4k count=1` to zero the superblock, then create a new filesystem with mkfs.ext4.

Answer

Run `tune2fs -j /dev/sda1` to add a journal to the filesystem.

Question 9

An organization runs a critical application on a Linux server that stores its data on a 500GB LVM logical volume named /dev/vg_data/lv_app. The application must remain operational with minimal disruption, so unmounting the volume is not acceptable. The administrator needs to create a full backup of the logical volume to an external 1TB USB drive attached via eSATA. The backup must capture a point-in-time consistent state of the filesystem. The logical volume is formatted with XFS. Which of the following procedures best achieves this goal while minimizing downtime?

Accepted Answer

Create an LVM snapshot volume of /dev/vg_data/lv_app, mount the snapshot to a temporary directory, and use rsync to copy the data to the USB drive.. It uses an LVM snapshot to capture a point-in-time consistent state of the XFS filesystem without unmounting the original volume. The snapshot is mounted read-only, and rsync copies the data to the USB drive, ensuring minimal disruption to the running application. This approach leverages LVM's copy-on-write mechanism to freeze the filesystem state at the snapshot creation moment.

Answer

Unmount the logical volume, use tar to create an archive on the USB drive, then remount the volume.

Answer

Use dd to clone the logical volume directly to the USB drive while the volume is mounted.

Answer

Create an LVM snapshot volume and then use cp -a to copy the snapshot volume's contents directly without mounting.

Question 10

A system administrator needs to create a RAID 10 array using four disks: /dev/sdb, /dev/sdc, /dev/sdd, /dev/sde. Which TWO commands correctly achieve this?

Accepted Answer

mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde. Option A is correct because `mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde` uses the numeric level 10, which mdadm accepts for a RAID 10 (striped mirror) array, and correctly specifies all four member disks with `--raid-devices=4`. Option C is also correct because mdadm accepts the alias `--level=raid10` for the same RAID 10 personality, and the rest of the command properly creates /dev/md0 across the four named devices. Option B is wrong because `--level=1` creates a RAID 1 mirror, not RAID 10, even though four devices are listed. Option D is wrong because `--level=0` builds a RAID 0 stripe over only two disks and the `--add /dev/md1` syntax does not create a RAID 10 array. Option E is wrong because `--raid-devices=2` with `--level=10` would only use two disks and cannot form the required four-disk RAID 10 layout.

Answer

mdadm --create /dev/md0 --level=1 --raid-devices=4 /dev/sdb /dev/sdc /dev/sdd /dev/sde

Answer

mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sdb /dev/sdc --add /dev/md1

Answer

mdadm --create /dev/md0 --level=10 --raid-devices=2 /dev/sdb /dev/sdc

Question 11

An administrator wants to use /dev/sdb for a new ext4 filesystem. Which step must be performed first?

Accepted Answer

Create a partition table on /dev/sdb using fdisk.. Before creating a filesystem on a new disk, a partition table must be created to define the disk's layout. The correct answer is D because /dev/sdb represents the whole disk, and mkfs.ext4 expects a partition (e.g., /dev/sdb1) rather than the raw disk. Using fdisk to create a partition table and at least one partition is the mandatory first step.

Answer

Mount /dev/sdb to a directory using mount.

Answer

Create the ext4 filesystem directly on /dev/sdb using mkfs.ext4.

Answer

Run partprobe /dev/sdb to update the kernel partition table.

Question 12

A server has an LVM volume group vg_data created with the default PE size, and the administrator needs to extend the logical volume lv_app by exactly 12 GiB at runtime while the XFS filesystem on it is mounted. Executing 'lvextend -L +12G /dev/vg_data/lv_app' succeeds, but 'xfs_growfs' reports the filesystem is already at maximum size and no additional space becomes usable. Which action should the administrator take to make the added space usable without unmounting the filesystem?

Accepted Answer

Run 'xfs_growfs -d /mountpoint' so the data section is expanded to fill the enlarged logical volume.. After lvextend enlarges the logical volume, the filesystem must be told to expand into the new blocks. XFS supports online growth, so xfs_growfs against the mount point with the -d flag extends the data section to fill the enlarged device. Simply extending the LV leaves the filesystem geometry untouched, which is why it still reports the previous maximum size.

Answer

Run 'lvextend -l +100%FREE /dev/vg_data/lv_app' to force LVM to reclaim the newly allocated extents.

Answer

Run 'xfs_growfs /mountpoint' again using the block device path /dev/vg_data/lv_app as the argument instead of the mount point.

Answer

Unmount the filesystem, run 'xfs_repair -n /dev/vg_data/lv_app', then remount and grow it.

Question 13

A file server exports /srv/data over NFS. Users report that files created by one client are not immediately visible to other clients that have the same directory mounted, even though the files exist on the server. The administrator confirms all clients mount the export with the same options. Which action should the administrator take to make newly created files immediately visible to all NFS clients?

Accepted Answer

Add the actimeo=0 export option to /etc/exports and re-export the filesystem.. The visibility delay is caused by client-side attribute and directory-entry caching, not by the server failing to write data. Reducing the cache lifetime with actimeo forces clients to revalidate attributes and directory contents against the server on each access, so new files appear promptly. Other export options affect durability or mount visibility, not cache staleness.

Answer

Add the nohide export option to /etc/exports and re-export the filesystem.

Answer

Add the sync export option to /etc/exports and re-export the filesystem.

Answer

Add the noac export option to /etc/exports and re-export the filesystem.

Question 14

A server hosts a 4 TB XFS filesystem on /dev/vg_data/lv_media, mounted at /srv/media. The volume group has 200 GB of free extents. The administrator needs to enlarge the filesystem by 100 GB without unmounting it. Which command sequence accomplishes this?

Accepted Answer

lvextend -L +100G /dev/vg_data/lv_media && xfs_growfs /srv/media. Extending a live XFS filesystem on LVM requires two distinct steps: grow the logical volume with lvextend using a relative size such as +100G, then expand the filesystem with xfs_growfs pointed at the mount point. XFS cannot be shrunk, and it is grown online, so no unmount is needed in this scenario.

Answer

lvresize -L 100G /dev/vg_data/lv_media && xfs_growfs /srv/media

Answer

lvextend -L +100G /dev/vg_data/lv_media && resize2fs /dev/vg_data/lv_media

Answer

lvextend -L +100G /dev/vg_data/lv_media && xfs_growfs /dev/vg_data/lv_media

Question 15

A Linux administrator is configuring iSCSI storage on a server that must automatically discover and log in to a target at boot. The administrator has already installed the open-iscsi package and started the iscsid service. Which two actions are required to ensure the target is connected automatically after a reboot? (Choose two.)

Accepted Answer

Run iscsiadm -m node -T -p --login to establish the session.. Automatic iSCSI connection at boot requires two actions: discovering the target so its node record exists in the local database, and logging in to that node so the session is established and marked for automatic startup. The open-iscsi service then reconnects the recorded nodes when iscsid starts.

Answer

Run iscsiadm -m session -P 3 to print the session details and save them to /etc/iscsi/session.conf.

Answer

Edit /etc/fstab to include the iSCSI target IQN and portal address as a mount source.

Answer

Run iscsiadm -m iface -I default -o new to create a new iSCSI interface.