Moving virtual workloads from one physical server to another with no downtime is called

February 1, 2021
Last updated on June 1, 2021

VMware vMotion is a vSphere feature that migrates a powered-on virtual machine (VM) between compatible physical servers with complete transaction integrity and zero downtime. VMware vMotion unlocks many of VMware’s novel technologies, including vSphere Distributed Resource Scheduler (DRS), vSphere High Availability (HA) and vSphere Distributed Power Management (DPM).

Learn what VMware vMotion is, how it works and how you can leverage it to migrate your VM workloads in this post.

What Can VMware vMotion Do?

Organizations can use VMware vMotion for several purposes, including migrations, automation and scheduling.

Live migration of VMs

No application can afford downtime in today’s fast-paced and ever-evolving business environment. VMware vMotion can help you avoid downtime, especially for events where you can foretell that system downtime is imminent, such as natural disasters, relocation or maintenance.

By migrating an entire running VM from one ESXi host to another, VMware vMotion brings invaluable benefits, including:

• Undertaking hardware maintenance without disrupting business operations and scheduling downtime.
• Optimizing VMs automatically within resource pools.
• Moving VMs from underperforming or failing servers to performing ones.

Automation and scheduling

VMware vMotion’s automated migration feature allows IT administrators to schedule the migration of VMs at predefined times. This unlocks many vSphere features such as DRS, HA and DPM. For example, DRS uses VMware vMotion to group multiple ESXi hosts into resource pools.

As such, VMs within a DRS cluster can move dynamically between any of the hosts within the cluster and balance resource consumption with no system downtime. If desired, you can also isolate resource pools among different business units and redistribute the VMs among the physical servers automatically.

Long-distance migration

If your infrastructure is large enough—spanning across multiple countries or locations—you can leverage vMotion’s long-distance migration feature to migrate VMs. VMware released long-distance vMotion in vSphere 6.0 and later versions to facilitate migrations between physical servers separated by high network round-trip times (RTTs).

Organizations can use long-distance migration to upgrade their datacenters, balance workloads and avoid natural disasters. For example, suppose there is a tornado coming to Oklahoma. In that case, you could use VMware vMotion’s long-distance migration tool to migrate VMs to another location that will not be affected by the disaster.

Datastore migration

Besides changing the physical server on which the VM is running, you can also change the VM’s datastore through a process popularly known as Storage vMotion (SvMotion). With SvMotion, both the VM’s state and virtual storage move to new locations. SvMotion, which is available in Sphere 5.1 and later releases, allows IT administrators to optimize disks for performance and convert between different disk types. It also simplifies maintenance and upgrades of virtual machines.

How Does VMware vMotion Work?

vMotion takes advantage of VMware’s core technologies such as disk snapshots, snapshot consolidation and redo logs to execute the migration process. vMotion’s migration is a three-step process involving:

1. Compatibility checks

This is the first step in moving VMs between hosts. The vCenter Server performs checks to ensure that both the source and destination hosts are compatible. Compatibility checks help prevent configuration problems arising from:

• Migration to a distributed switch that is malfunctioning.
• Migration from distributed to standard switches.
• Migration between different versions of distributed switches.
• Incompatible media access control (MAC) addresses on the destination host.

2. Handshakes

During the handshake process, the vCenter Server generates metadata. The metadata contains information about the VM to be live-migrated, including the VM’s configuration details, source, destination ESXi hosts, and vMotion network specifications. The vCenter Server then shares the migration metadata between the source and the destination ESXi hosts.

3. Migration

By now, all the communication channels and processes are ready to kick-start the live migration of the VMs. To ensure seamless live migration, vMotion transfers the memory state of each VM in three main phases:

• Guest trace phase. This phase prepares the guest for live migration by transferring the memory from the source to the destination host. At this stage, tracing all the guest memory pages on the source host is necessary for the vMotion to know which memory pages get overwritten during live migration.
• Pre-copy phase. Since the guest continues to run and can actively alter its memory status during the migration, the VM memory gets copied from the source to the destination iteratively. During the first iteration, all the guest memory gets copied. For subsequent iterations, only the pages whose contents changed during the previous iteration gets copied. The number of iterations depends on how the guest memory gets changed due to ongoing operations.
• Switchover phase. This is the final stage of live migration, where the guest pauses the processing momentarily on the source host. The virtual machine monitor (VMM) suspends the source VM and resumes it on a target ESXi host.

What Does Storage vMotion Offer?

Storage vMotion (SvMotion) is VMware vMotion’s companion feature that allows live migration of a running VM’s file system from one datastore to another. You can place the VM and all its storage components in a single location or separate locations during live migration. Like vMotion, SvMotion does not affect downtime, nor does it endanger data consistency.

You can leverage SvMotion for various use cases, including:

• Migrating virtual disks (vDisks) from an old storage area network (SAN) to a new storage system.
• Load-balancing the available virtualized resources to ensure a VM gets the storage performance it needs.
• Moving vDisks from a local ESXi server to a SAN.
• Taking physical storage down for maintenance.
• Replicating virtual machines and their associated vDisks to a remote site during disaster recovery.
• Converting between different virtual disk formats.

How Can You Use vMotion to Migrate Workloads to Azure?

Cloud adoption has increased significantly in recent years due to its greater scalability, improved performance and cost-efficiency. Migrating VMware workloads to Azure is now friction-free, thanks to Azure VMware Solution. Azure VMware Solution is a fully managed Platform as a Service (PaaS) offering that includes vSphere, vSAN, NSX-T, vCenter and other tools that delivers a complete VMware environment in Azure.

Organizations can leverage Azure VMware Solution to run native VMware workloads on Azure. Since VMware workloads run directly on Azure bare-metal infrastructure, there is no nested virtualization. As such, you can continue to use your existing VMware tools without worrying about scaling, patching or re-platforming your VMs.

Beyond building and configuring the VMware environment on Azure, you can use vMotion to live-migrate on-premises VM workloads to Azure as you would between VMware sites. As VMware workloads begin to run in Azure, organizations can take advantage of Azure’s scalability, accelerated provisioning cycles, and security to modernize their applications.

For example, you can use existing VMware templates in your on-premises environment to create new VMware VM instances and run them privately in Azure. Since the VMs created in Azure are visible and accessible in the vSphere environment, you can flexibly manage their resources as you would normally in vCenter Server. You can also manage virtual machine resources in Azure.

Parallels RAS Can Provision VDI on Azure

Server virtualization, VMware’s underpinning technology, has proven itself revolutionary in minimizing IT expenses while enhancing agility and efficiency in organizations. However, server virtualization may no longer make sense in the wake of an expanding mobile workforce, the popularity of bring-your-own-devices (BYODs), and tighter IT budgets.

As you consider migrating to the cloud, perhaps it is time to refocus your strategies on desktop virtualization solutions. Moving virtual desktops and applications to the cloud can help you realize the significant benefits of virtualization, including centralized management, simplified administration and enhanced security.

Parallels® Remote Application Server (RAS) is your go-to virtual desktop infrastructure (VDI) solution when it comes to deploying virtual desktops and applications on Azure. Organizations can leverage Parallels RAS on Azure to allow their employees immediate and secure access to virtual desktops and applications across the internet without worrying about complex firewall configurations.

Parallels RAS is simple to deploy on Azure. With inbuilt automation capabilities that include Azure VM templates and configuration wizards, you can deploy a full-featured Parallels RAS appliance in less than 30 minutes. Besides Azure’s security features, you can also take advantage of Parallels RAS cutting-edge security features such as multi-factor authentication (MFA) to secure virtual desktops and applications.

Most importantly, Parallels RAS provides multi-cloud capabilities, which mitigates against vendor lock-in risks. You can also deploy it on Amazon Web Services (AWS) and Google Cloud Platform (GCP).

Download your 30-day Parallels RAS trial today, and make the most of VDI management on Azure!