You're viewing documentation for a prior version of Migrate for Compute Engine (formerly Velostrata). You can continue using this version, or use the current version.

Google Cloud reference architecture

Migrate for Compute Engine provides a path for you to migrate your virtual machines (VMs) running on VMware vSphere to Compute Engine. Migrate for Compute Engine can also migrate your physical servers and Amazon EC2 or Azure VMs to Compute Engine.

The primary components of a Migrate for Compute Engine installation are:

In Google Cloud:

  • The Velostrata Manager on Google Cloud manages all components and orchestrates migrations. It also serves the Migrate for Compute Engine UI.
  • Cloud Extensions handle storage migrations and serve data to migrated workloads during migration. A Cloud Extension is a pair of Cloud Edge nodes.
  • The Migrate for Compute Engine Exporter creates Google Cloud Persistent Disks when detaching disks.


  • The Velostrata On-Premises Backend virtual appliance serves data from VMware to the cloud extension.
  • The Migrate for Compute Engine vCenter Plugin connects vCenter vSphere to the Velostrata Manager.


  • The Migrate for Compute Engine Importer serves data from AWS Elastic Block Store volumes to Cloud Extensions.

On Azure:

  • The Migrate for Compute Engine Importer serves data from Azure disks to Cloud Extensions.

Migrate for Compute Engine Architecture, showing all components of the infrastructure

Core technologies

Migrate for Compute Engine decouples VMs from their storage and introduces capabilities that ease your move to Google Cloud, including:

  • Easy deployment: Install Migrate for Compute Engine virtual appliances in just a few steps, without installing agents on servers.
  • Simple management in vCenter for VMware migrations: A plug-in flattens the learning curve for VMware administrators. Integration with tasks, events, and alarms provides visibility and control over migration.
  • Secure by design: Data transfers between Migrate for Compute Engine components use SSL and AES-128 encryption. Data at rest is de-duplicated, compressed, and encrypted with AES-256.
  • Boot over WAN: Migrate for Compute Engine performs a native boot in the cloud from your VMs in a few minutes, regardless of image size. While the image boots, Migrate for Compute Engine adapts it for the target environment. No changes to the application, original image, storage, drivers, or networking are necessary.
  • Intelligent streaming: Migrate for Compute Engine prioritizes the data necessary for an application to run and moves that data to the cloud first. Other data is streamed to the cloud when needed.
  • Multi-tier caching and optimization: Migrate for Compute Engine includes a multi-tier, read-write cache in the cloud. This cache stores data needed by the application. De-duplication, pre-fetching, asynchronous write-back, and network optimizations further accelerate the migration, reducing migration bandwidth by up to 75% in production migrations.
  • Resiliency: Migrate for Compute Engine Cloud Extensions use an active-passive configuration across two availability zones. Data is written in both zones and then asynchronously transferred back on premises to reduce the risk of data loss. Optionally, writes can persist solely in the cloud for development and testing.

    The recovery point objective (RPO) is the maximum acceptable length of time during which data might be lost due to an incident. Migrate for Compute Engine's architecture ensures a 30-second RPO for sync to Google Cloud Storage in the rare case of a dual zone failure and a 1-hour RPO for sync on-premises.

  • Supports multiple operating systems: See the list of Supported OS Versions.


A typical Migrate for Compute Engine deployment architecture consists of two parts:

The following diagram depicts a typical Migrate for Compute Engine deployment with Google Cloud.

Migrate for Compute Engine deployment showing the logical connections between all components

On the left is the corporate data center (on-premises), and on the right is a Google Cloud Virtual Private Cloud. The two connect using a Cloud VPN or Cloud Interconnect.

Other supported deployment architectures include:

  • Cloud-to-cloud migrations from AWS to Google Cloud
  • Hybrid migrations from both on-premises and AWS to Google Cloud

On Google Cloud

Use the Google Cloud Marketplace to deploy the Velostrata Manager on Google Cloud. It orchestrates migration operations and serves the web UI. The Velostrata Manager connects with the Velostrata On-Premises Backend virtual appliance and accesses Google Cloud API endpoints as well as Google Cloud's operations suite Monitoring and Logs services.

Once you launch the Velostrata Manager and connect it to the Velostrata Backend, create Cloud Extensions, which manage storage migration. The Cloud Extension nodes (also known as Cloud Edge nodes) run in pairs in separate Google Cloud zones.

In general, the Velostrata Manager and Cloud Extension require inbound access from the corporate data center to Google Cloud. Inbound iSCSI access from on-premises VMs migrated to Google Cloud into the Cloud Extension nodes is necessary to migrate storage.

Subnets where Cloud Extension nodes are deployed must allow outbound access to certain services, such as Cloud Storage and Google Cloud's operations suite Monitoring.

Corporate data center

When performing on-premises to cloud migrations, the Velostrata On-Premises Backend virtual appliance on VMware:

  • Establishes a secure datapath with the Cloud Extension nodes.
  • Starts and stops VMs using VMware APIs.
  • Performs storage operations against virtual machine disks (VMDKs) using the VMware Storage API.


For migrations from AWS to Google Cloud, the Velostrata Manager launches Importer instances on AWS as needed to migrate AWS EC2 source workloads and their EBS volumes. These instances run only when data is being migrated.


For migrations from Azure to Google Cloud, the Velostrata Manager launches Importer instances on Azure as needed to migrate Azure source workloads and their disks. These instances run only when data is being migrated.

What's next

For a quick walkthrough of Migrate for Compute Engine's functionality, see Getting started with Migrate for Compute Engine.

For more information about a recommended Virtual Private Cloud configuration, see Google Cloud account and Virtual Private Cloud (VPC) setup requirements.