Linux LVM & Storage Interview questions and Answers | Logical Volume Manager (LVM) Concepts

Linux Storage Challenge - Filesystems & LVM

💾 Linux Storage & Volume Management Challenge

Master Linux Filesystems, Partitioning, LVM, and RAID concepts. **Pass with 80% to proceed to the next difficulty level.**

Filesystem Basics: 0/10 (0%)

LVM Concepts: 0/10 (0%)

RAID & Advanced: 0/10 (0%)

Level 1: Filesystem & Partitioning Fundamentals

1.1 Which command is used to display disk space usage for mounted filesystems in a human-readable format?

A. `lsblk` B. `df -h` C. `du -sh`

**Correct Answer: B. `df -h`**. `df` reports total disk space, and `-h` makes it human-readable (e.g., 10G, 500M). `du` reports file/directory space usage.

1.2 What must be done to a disk partition after creating a filesystem (e.g., ext4) but before a user can access the files?

A. Run `fsck` B. Run `pvcreate` C. Mount the filesystem

**Correct Answer: C.** The **mount** command attaches the filesystem to a directory in the existing filesystem tree (the mount point).

1.3 Which tool is used to create and manipulate disk partitions on a Linux system, often replacing the older `fdisk`?

A. `mkfs` B. `gdisk` or `parted` C. `lvmcreate`

**Correct Answer: B. `gdisk` or `parted`**. `gdisk` is commonly used for modern GPT partitions, while `parted` is flexible for both MBR and GPT. `fdisk` is for MBR partitions.

1.4 The command `mkfs.ext4 /dev/sdb1` is used to:

A. Check the integrity of the filesystem. B. Create a new ext4 filesystem on the specified partition. C. Mount the specified partition.

**Correct Answer: B.** `mkfs` stands for **M**a**k**e **F**ile**S**ystem.

1.5 Which directory contains device files like `/dev/sda` and `/dev/cdrom`?

A. `/etc` B. `/var` C. `/dev`

**Correct Answer: C. `/dev`**. This directory holds device nodes, which are special files used to interact with hardware.

1.6 The UUID (Universally Unique Identifier) is primarily used in the `/etc/fstab` file for what purpose?

A. To specify the default permissions for the mounted filesystem. B. To reliably identify a filesystem regardless of its device name (`/dev/sda1`). C. To determine the size of the partition.

**Correct Answer: B.** Device names like `/dev/sda1` can change if you add or remove drives. The **UUID** is a permanent, unique label for the filesystem.

1.7 What is the primary difference between a Hard Link and a Soft (Symbolic) Link?

A. Hard links can link to directories; soft links cannot. B. Hard links share the same inode; soft links create a new file that points to the original path. C. Hard links can link across different filesystems; soft links cannot.

**Correct Answer: B.** Hard links are file-system specific and point to the same data block (same inode). Soft links are like shortcuts and point to a path.

1.8 Which of the following is an example of a Journaling Filesystem?

A. FAT32 B. XFS C. ext2

**Correct Answer: B. XFS**. Journaling filesystems (like ext3, ext4, XFS, Btrfs) track metadata changes to ensure rapid recovery after a crash. ext2 is not journaling.

1.9 Which utility is used to check and repair a Linux filesystem that was not properly unmounted?

A. `mke2fs` B. `badblocks` C. `fsck`

**Correct Answer: C. `fsck`** (File System Check). Note: You must unmount a filesystem before running `fsck` to prevent data corruption.

1.10 What file contains the configuration data used by the system to automatically mount filesystems at boot?

A. `/boot/grub/menu.lst` B. `/etc/fstab` C. `/proc/mounts`

**Correct Answer: B. `/etc/fstab`** (File System Table). This file is read at boot to determine which partitions to mount, where to mount them, and with what options.

**End of Filesystem Basics. Click "Next Level" to continue.**

Level 2: Logical Volume Manager (LVM) Concepts

2.1 What does LVM stand for?

A. Linux Virtual Machine B. Logical Volume Manager C. Low-Volume Memory

**Correct Answer: B. Logical Volume Manager**. LVM provides an abstraction layer over physical storage, allowing flexible resizing.

2.2 What is the fundamental, lowest-level building block of LVM, created from a disk or partition?

A. Logical Volume (LV) B. Volume Group (VG) C. Physical Volume (PV)

**Correct Answer: C. Physical Volume (PV)**. A PV is an actual disk or partition marked for LVM use using `pvcreate`.

2.3 A Volume Group (VG) is essentially:

A. The partition that holds the bootloader. B. A pool of storage space created by combining one or more Physical Volumes. C. A fixed-size partition that cannot be resized.

**Correct Answer: B.** The VG is the reservoir of storage from which Logical Volumes are carved.

2.4 Which command would you use to create a Logical Volume named `data_lv` with a size of 50GB inside a Volume Group named `vg_storage`?

A. `vgcreate -L 50G data_lv /dev/sdb` B. `pvcreate -L 50G data_lv vg_storage` C. `lvcreate -n data_lv -L 50G vg_storage`

**Correct Answer: C. `lvcreate -n data_lv -L 50G vg_storage`**. `lvcreate` is for LVs, `-n` names it, and `-L` sets the size.

2.5 The primary advantage of LVM over traditional partitioning is:

A. It is always faster than non-LVM storage. B. It allows for flexible online resizing (extending/shrinking) of volumes. C. It automatically provides data redundancy (mirroring).

**Correct Answer: B.** While LVM can be configured for speed/redundancy, its core strength is the flexibility of resizing volumes without downtime.

2.6 Which step is often required before shrinking a Logical Volume (LV) and its filesystem?

A. Run `pvmove`. B. The filesystem on the LV must be unmounted and resized first. C. The system must be rebooted into single-user mode.

**Correct Answer: B.** Shrinking is dangerous. The filesystem (e.g., ext4) must be made smaller **first** to ensure no data is lost when the underlying LV shrinks.

2.7 What LVM component represents the smallest unit of disk space allocation?

A. Inode B. Physical Extent (PE) C. Logical Volume (LV)

**Correct Answer: B. Physical Extent (PE)**. PEs are small, fixed-size chunks of a PV. Logical Volumes are made of Logical Extents (LEs) which map to PEs.

2.8 What is the command used to increase the size of an existing Logical Volume named `home_lv`?

A. `lvreduce` B. `lvextend` C. `vgextend`

**Correct Answer: B. `lvextend`**. This increases the LV size. You'll typically follow this with a filesystem resize command like `resize2fs`.

2.9 What feature of LVM allows you to create a read-only, point-in-time copy of a Logical Volume?

A. Mirroring B. Snapshot C. Striping

**Correct Answer: B. Snapshot**. Snapshots are vital for creating consistent backups while the system is running.

2.10 If a Volume Group runs out of space, how can you non-destructively add more storage to it?

A. Run `vgreduce` on an existing LV. B. Create a new PV and use `vgextend` to add it to the VG. C. Delete an old LV and create a new, larger one.

**Correct Answer: B.** The process is: 1) `pvcreate` new disk/partition, 2) `vgextend` the new PV into the existing VG.

**End of LVM Concepts. Click "Next Level" to continue.**

Level 3: RAID and Advanced Storage Concepts

3.1 What does RAID stand for?

A. Redundant Access Independent Disks B. Randomized Array of Inodes & Data C. Redundant Array of Independent Disks

**Correct Answer: C. Redundant Array of Independent Disks**. RAID combines multiple physical disks into a single logical unit for redundancy, performance, or both.

3.2 Which RAID level provides striping for improved performance but offers no redundancy?

A. RAID 1 B. RAID 0 C. RAID 5

**Correct Answer: B. RAID 0**. It uses striping for speed. If one disk fails, all data is lost.

3.3 Which command is used in Linux to manage Software RAID arrays?

A. `raidctl` B. `lvm` C. `mdadm`

**Correct Answer: C. `mdadm`** (`m`ultiple `d`evice `adm`inistration). This is the standard utility for managing Linux's MD software RAID.

3.4 What is the space efficiency of a RAID 5 array with four 1TB disks?

A. 4TB (100% efficiency) B. 2TB (50% efficiency) C. 3TB (75% efficiency)

**Correct Answer: C. 3TB**. RAID 5 uses one disk's space for parity data ($N-1$ disks of capacity). $(4-1) \times 1TB = 3TB$.

3.5 What is a Storage Area Network (SAN) in a corporate Linux environment?

A. A network of servers that share files over NFS or SMB. B. A dedicated high-speed network that provides block-level storage (like a local disk) to servers. C. A service that backs up server data over the internet.

**Correct Answer: B.** SANs (using Fiber Channel or iSCSI) present storage as raw **block devices** to servers.

3.6 What is the primary purpose of the Swap Space partition in Linux?

A. To store kernel log files. B. To act as a cache for files being moved between disks. C. To extend the available RAM by moving inactive memory pages to disk.

**Correct Answer: C.** Swap space acts as virtual memory when physical RAM runs low.

3.7 The `rsize` and `wsize` options are commonly used when mounting which type of network filesystem?

A. SMB/CIFS B. NFS (Network File System) C. FUSE

**Correct Answer: B. NFS**. These options control the read and write block size for network transfers, impacting performance.

3.8 In the context of disk partitioning, what is the key advantage of GPT (GUID Partition Table) over the older MBR (Master Boot Record)?

A. It can only support two partitions. B. It supports volumes larger than 2TB and up to 128 primary partitions by default. C. It can only be used with the ext2 filesystem.

**Correct Answer: B.** MBR is limited to 2TB and four primary partitions (or three primary + one extended). GPT resolves both issues.

3.9 A Thin-Provisioned Logical Volume in LVM allows you to:

A. Use smaller PEs for faster performance. B. Allocate more storage space to the volume than is physically available in the Volume Group. C. Automatically resize the volume group when it runs low on space.

**Correct Answer: B.** Thin provisioning lets you overcommit storage, allocating physical space only as data is written.

3.10 The Btrfs filesystem is known for which of the following advanced features?

A. Guaranteed faster boot times than ext4. B. Automatic conversion of MBR to GPT partitions on the fly. C. Built-in support for volume management, copy-on-write, and checksumming.

**Correct Answer: C.** Btrfs (B-tree File System) is a modern, advanced filesystem that combines features typically found in LVM and RAID within the filesystem itself.

**Storage Mastered! Click "Finish Quiz" to see your final summary.**

Final Quiz Summary 📋

Related Topics & Tags

Linux Storage LVM RAID Filesystem ext4 fstab Partitioning GPT mdadm Btrfs SysAdmin BlockDevices DiskManagement

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