VHDX Support

Bug Reference

CLOUDSTACK-6288

Branch

4.4, master

Introduction

As enterprise workloads for virtual environments grow in size and in performance demands, virtual hard disk (VHD) formats need to accommodate them. Hyper-V in Windows Server 2012 introduces a new version of the VHD format called VHDX, which is designed to handle current and future workloads. VHDX has a much larger storage capacity than the older VHD format. It also provides data corruption protection during power failures and optimizes structural alignments of dynamic and differencing disks to prevent performance degradation on new, large-sector physical disks.

Currently in cloudstack, only VHD virtual disk format is supported for Hyper-V. With this feature support for VHDX format will also be enabled for Hyper-V.

Purpose

This is a feature specification for supporting VHDX image format for Hyper-V.

References

• Hyper-V Virtual Hard Disk Format Overview
• Why use VHDX?

Document History

Glossary

Instance/vm - Virtual machine running on a hypervisor. The terms may be used interchangeably.

Feature Specifications

1. A user should be able to register a template of type VHDX for Hyper-V. Functionality of being able to register a template of type VHD for Hyper-V should continue to work
2. A user should be able to create an instance on Hyper-V from template of type VHDX as well as VHD.
3. Following operation should work for volumes of type VHDX.
   1. Migrating a volume from one storage pool to another.
   2. Downloading a volume.
   3. Creating a template from volume.
   4. Downloading a template.
   5. Storage motion of volumes.
      1. Live migrating a volume attached to a running vm from one storage pool to another.
      2. Live migrating an instance with its volumes from host to another while the volumes migrate from one storage pool to another.
4. All data disks that are allocated and created on Hyper-V will be of type VHDX.
5. A cloudstack Hyper-V setup that has been upgraded from 4.3 may have existing root and data volumes of type VHD. All the supported operations; as listed in point 3 above; on these volumes should continue to work.
6. An instance can have virtual disks of type VHDX and VHD, both attached to it.

Test Guidelines

Functional

• User should be able to register a template of type VHDX or VHD for Hyper-V.
• User should be able to create instances from templates of type VHDX and VHD.
• Validate all the supported operations on volumes of type VHDX and VHD. Supported operations include
  • Migrating a volume from one storage pool to another.
  • Downloading a volume.
  • Creating a template from volume.
  • Downloading a template.
  • Storage motion of volumes.

Negative

Support-ability Characteristics

Logs can be looked up at the following location

• The Hyper-V agent logs can be seen in windows event viewer on the respective hosts. The logs can be filtered by source "CloudStack Hyper-V Agent".

Configuration Characteristics

Users Communities

Supported Hypervisor

This feature is implemented for Windows Server 2012 R2 and Hyper-V 2012 R2 (Core).

Use cases

Architecture and Design description

Database modifications

There are no database schema changes for this feature.

Web Services APIs

UI flow

IP Clearance

No IP dependencies are introduced by this feature.

Appendix

Appendix A:

Appendix B: