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Title and Scenario

This lab focuses on advanced storage management and device handling on Azure-based Linux virtual machines. You will work with Logical Volume Manager (LVM) and NVMe-backed disks, performing controlled modifications to volume groups and logical volumes while preserving filesystem integrity and operational consistency.

The exercises are designed to simulate real-world storage expansion, reduction, device mapping inconsistencies, and cloud-specific disk behaviors. You must approach each task methodically, validating state before and after every operation.

The goal is to strengthen your understanding of:

  • LVM volume group and logical volume lifecycle management
  • Filesystem integrity considerations during resize operations
  • Azure disk device naming and symlink behavior
  • NVMe controller enumeration and udev-based device mapping
  • Troubleshooting storage layer inconsistencies without data loss

Deployment

Storage / LVM

Deploy to Azure

Storage / NVME

Deploy to Azure

Skills Required

  • Strong understanding of LVM concepts (PV, VG, LV)
  • Filesystem resize behavior (extend vs reduce considerations)
  • Comfort inspecting block devices and device-mapper output
  • Familiarity with Azure disk presentation models
  • Understanding of NVMe devices and controller enumeration
  • Awareness of udev rule mechanics and persistent device naming

Recommended Prerequisites

  • Experience working with lvs, vgs, pvs, and lsblk
  • Understanding of safe filesystem resizing principles
  • Familiarity with Azure LUN assignment concepts
  • Basic understanding of udev rules and device symlink creation

Objectives

By completing these exercises, you should be able to:

  • Safely extend and reduce logical volumes
  • Differentiate between resizing a logical volume and resizing a filesystem
  • Identify when additional physical volumes are required
  • Diagnose device mapping inconsistencies in Azure NVMe environments
  • Restore expected Azure disk symlink behavior using udev rules
  • Maintain filesystem integrity throughout all storage operations

Environment Overview

Two separate Azure-based environments are provided:

  1. LVM-based VM with multiple volume groups and logical volumes.
  2. NVMe-based VM where disks are presented as NVMe devices instead of traditional SCSI.

Both environments simulate common production storage challenges.

Your Mission

Work through each exercise sequentially.

For LVM:

  • Extend, reduce, and validate logical volumes and filesystems.
  • Introduce additional disks and integrate them into volume groups.
  • Identify and resolve issues related to volume group capacity and filesystem resizing.

For NVMe:

  • Inspect device mappings and controllers.
  • Identify missing Azure symlinks.
  • Apply the appropriate udev rule to restore expected behavior.
  • Validate device mapping after reboot.

Perform all steps carefully and validate after each operation.

Analytical Guidance

When working with LVM:

  • Always inspect current layout before modifying it.
  • Distinguish between resizing the logical volume and resizing the filesystem.
  • Never assume filesystem resizing occurs automatically.
  • When reductions are required, ensure filesystem safety before shrinking logical volumes.
  • Validate mount points and data consistency after each modification.

When working with NVMe:

  • Compare lsblk output with Azure symlink paths.
  • Confirm NVMe controllers using nvme list.
  • Understand how Azure device symlinks are generated.
  • Apply udev rules carefully and validate after reboot.

Validation Criteria

LVM Exercise Validation:

  • Logical volumes reflect the requested size changes.
  • Volume groups properly include added physical volumes.
  • Filesystems are consistent and mounted correctly.
  • No data loss occurs during extend or reduce operations.
  • All mount points (e.g., /opt/data01) are accessible and consistent after resizing.

NVMe Exercise Validation:

  • NVMe controllers are properly enumerated.
  • Azure symlink paths exist under /dev/disk/azure after applying udev rules.
  • Device mappings persist correctly across reboots.

Documentation Expectations

Your documentation should include:

  • Initial layout inspection output
  • Explanation of capacity calculations before resizing
  • Observed errors and their interpretation
  • High-level explanation of how the issue was resolved
  • Validation outputs confirming successful operations
  • Observations about Azure disk presentation differences

What Not To Do

  • Do not resize filesystems blindly.
  • Do not assume automatic filesystem expansion.
  • Do not reduce logical volumes without validating filesystem requirements.
  • Do not ignore errors when extending volume groups.
  • Do not assume Azure symlinks exist automatically in NVMe scenarios.

Real-World Context

In production environments:

  • Storage expansion is routine but must be performed safely.
  • Logical volume reduction is high-risk and requires careful validation.
  • Cloud providers may present disks differently depending on instance type.
  • Persistent device naming is critical for stable automation.
  • NVMe-based disks can disrupt legacy assumptions about device paths.

Understanding these behaviors prevents outages and data corruption.

Optional Advanced Exploration

  • Compare LVM behavior across XFS and ext4 filesystems.
  • Investigate how Azure maps LUN IDs to NVMe devices.
  • Analyze how udev rules generate /dev/disk/azure symlinks.
  • Create a repeatable storage validation checklist for production use.

Storage

Storage / LVM

Deploy this VM. This will automatically create a VM and set an initial LVM/filesystem structure.

Deployment: See the Deployment section.

For this exercise, it's recommended to use these commands:

lvs -o +devices
ls -l /dev/disk/azure/scsi1
  • Extend /dev/vgdata01/lvdata01 to use all available space on the volume group vgdata01.
  • Extend /dev/vgdata01/lvdata01, this time adding /dev/disk/azure/scsi1/lun1 to vgdata01.

    Don't resize the filesystem yet!

  • Reduce /dev/vgdata01/lvdata01 by 2GB of the total space assigned.
  • Check the filesystem /opt/data01
  • Extend /dev/vgdata01/lvdata01 to use all available space on the volume group vgdata01. This time extend the filesystem as well.
  • Reduce /dev/vgdata01/lvdata01 to 3GB.
  • Check the filesystem /opt/data01.
  • Extend /dev/vgdata03/lvdata02 to use all available space on the volume group vgdata02 as well the filesystem.
  • Add /dev/disk/azure/scsi1/lun4 to /dev/vgdata02 and extend all free space on /dev/vgdata02/lvdata02.

    Got any error? What you need to solve this?

  • Extend /dev/vgdata02/lvdata03 to use all available space on the volume group vgdata03 as well the filesystem.
  • Create and attach two new 4GB disks to be used with vgdata03, assign IDs 8 and 9.

    Another problem? How can you solve this?

  • Add the new LUNs 8 and 9 to vgdata03 and extend /dev/vgdata03/lvdata03.

Storage / NVME

Deploy this VM. This will automatically create a VM which uses NVME for all disks.

Deployment: See the Deployment section.

For this exercise, it's recommended to use these commands:

lsblk  -f
nvme list
ls -l /dev/disk/azure/scsi1
ls -l /dev/disk/azure
  • List the block device using lsblk -f
  • List all nvme controllers using nvme list
  • List the files and symlinks on /dev/disk/azure

    You may found the previous symlinks and files are missing

  • For this purpose we are going to install a new udev rule available here 
    wget https://raw.githubusercontent.com/Azure/azure-vm-utils/refs/heads/main/udev/80-azure-disk.rules -O /etc/udev/rules.d/80-azure-disk.rules
  • Reboot and check again /dev/disk/azure