App Volumes: VHD in-Guest vs Standard Mode

Technical comparison and recommended use cases

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INTRODUCTION

Omnissa App Volumes provides two distinct modes for delivering applications to Horizon users: the standard mode (VMDK/VMFS-based) and VHD in-guest mode, introduced to support non-persistent OS scenarios and advanced Instant Clone environments.

The choice between the two modes directly affects performance, scalability, and infrastructure requirements.

MODE COMPARISON

Standard Mode (VMDK)

• VMDK disk attach via vCenter API

• Mandatory needs a vSphere infrastructure as a prerequisite

• Limited support for multi-hypervisor environments

• Dependency on shared vSphere datastores

• Compatible with all Horizon desktop types

VHD in-Guest

• VHD mounted directly inside the guest OS

• Hypervisor-independent

• Compatible with Azure, AVD and physical environments

• VHD exposed via SMB share or UNC path

• Application packages and writable volumes are stored in a high-performance file share

• Compatible with all Horizon desktop types

TAKE NOTE! We can select the mode (VMDK or VHD) when installing the first App Volumes Manager. We can’t switch from VMDK to VHD mode, or from VHD to VMDK mode, after the first configuration.

VHD IN GUEST ARCHITECTURE

In this mode, the App Volumes Agent inside the guest mounts the VHD file from the configured UNC path using native Windows APIs. The AppStack content is then layered onto the filesystem via the App Volumes kernel filter driver, making applications available without extraction.

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Note: In VHD in guest mode, the AppStack .vhd file must be reachable via UNC path from the guest. Network latency to the share directly affects mount times.

WHEN TO CHOOSE VHD IN-GUEST

1

Reducing vCenter dependency

Environments with restrictive policies on vCenter API access or multi-cloud architectures.

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2

Physical desktops or RDSH

Scenarios where the workload runs on bare metal or RDS servers without vSphere hypervisor.

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3

Azure Virtual Desktop (AVD) environments

Non-vSphere infrastructure; inability to attach VMDK via vCenter.

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App Volumes: VHD in-Guest vs Standard Mode

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