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--- title: Enable VMware VMs (Modernized) for disaster recovery using Azure Site Recovery description: This article describes how to enable VMware VM replication for disaster recovery using the Azure Site Recovery service. author: Jeronika-MS ms.service: azure-site-recovery ms.topic: how-to ms.author: v-gajeronika ms.reviewer: v-gajeronika ms.date: 02/13/2026 # Customer intent: As a system administrator, I want to enable VMware VM replication to Azure for disaster recovery, so that I can ensure business continuity and seamless recovery in the event of a disaster. --- # Enable replication to Azure for VMware VMs - Modernized This article describes how to enable replication of on-premises VMware virtual machines (VM) to Azure. ## Prerequisites Before you begin, make sure your system meets the following criteria: - [Set up your on-premises source environment](vmware-azure-set-up-source.md). - [Set up your target environment in Azure](vmware-azure-set-up-target.md). - [Verify requirements and prerequisites](vmware-physical-azure-support-matrix.md). Important things to note include: - [Supported operating systems](vmware-physical-azure-support-matrix.md#replicated-machines) for replicated machines. - [Storage/disk](vmware-physical-azure-support-matrix.md#storage) support. - [Azure requirements](vmware-physical-azure-support-matrix.md#azure-vm-requirements) with which on-premises machines should comply. ### Resolve common issues - Each disk must be smaller than 4 TB when replicating to unmanaged disks and smaller than 32 TB when replicating to managed disks. - The operating system disk must be a basic disk, not a dynamic disk. - For generation 2 UEFI-enabled virtual machines, the operating system family must be Windows, and the boot disk must be smaller than 300 GB. ## Before you start When you replicate VMware virtual machines, keep this information in mind: - Your Azure user account needs to have certain [permissions](site-recovery-role-based-linked-access-control.md#permissions-required-to-enable-replication-for-new-virtual-machines) to enable replication of a new virtual machine to Azure. - VMware VMs are discovered every 15 minutes. It can take 15 minutes or more for VMs to appear in the Azure portal after discovery. When you add a new vCenter server or vSphere host, discovery can take 15 minutes or more. - It can take 15 minutes or more for environment changes on the virtual machine to be updated in the portal. For example, the VMware tools installation. - You can check the last-discovered time for VMware VMs: See the **Last Contact At** field on the **Configuration Servers** page for the vCenter server or vSphere host. - To add virtual machines for replication without waiting for the scheduled discovery, highlight the configuration server (but don't select it), and select **Refresh**. - When you enable replication, if the virtual machine is prepared, the process server automatically installs the Azure Site Recovery Mobility service on the VM. ## Enable replication Before you do the steps in this section, review the following information: - Azure Site Recovery now replicates directly to managed disks for all new replications. The process server writes replication logs to a cache storage account in the target region. These logs are used to create recovery points in replica managed disks that follow the naming convention `asrseeddisk`. - PowerShell support for replication to managed disks is available beginning with [Az.RecoveryServices module version 2.0.0](https://www.powershellgallery.com/packages/Az.RecoveryServices/2.0.0-preview) - At the time of failover, the recovery point that you select is used to create the target-managed disk. - VMs that you previously configured to replicate to target storage accounts aren't affected. - Replication to storage accounts for a new virtual machine is only available via a Representational State Transfer (REST) API and PowerShell. Use Azure REST API version 2016-08-10 or 2018-01-10 for replication to storage accounts. To enable replication, follow these steps: 1. Go to **Step 2: Replicate application** > **Source**. After you enable replication for the first time, select **+Replicate** in the vault to enable replication for additional virtual machines. 1. In the **Source** page > **Source**, select the configuration server. 1. For **Machine type**, select **Virtual Machines** or **Physical Machines**. 1. In **vCenter/vSphere Hypervisor**, select the vCenter server that manages the vSphere host, or select the host. This setting isn't relevant if you're replicating physical computers. 1. Select the process server. If you don't create any additional process servers, the built-in process server of the configuration server is available in the dropdown menu. The health status of each process server is indicated according to recommended limits and other parameters. Choose a healthy process server. You can't choose a [critical](vmware-physical-azure-monitor-process-server.md#process-server-alerts) appliance. You can either [troubleshoot and resolve](vmware-physical-azure-troubleshoot-process-server.md) the errors **or** set up a [scale-out process server](vmware-azure-set-up-process-server-scale.md). :::image type="content" source="./media/vmware-azure-enable-replication/ps-selection.png" alt-text="Enable replication source window."::: > [!NOTE] > Starting with [version 9.24](site-recovery-whats-new.md), additional alerts enhance the health alerts of process server. Upgrade the Site Recovery components to version 9.24 or later for all alerts to be generated. 1. For **Target**, select the subscription and resource group where you want to create the failed over virtual machines. Choose the deployment model that you want to use in Azure for the failed over VMs. 1. Select the Azure network and subnet that the Azure VMs connect to after failover. The network must be in the same region as the Site Recovery service vault. Select **Configure now for selected machines** to apply the network setting to all virtual machines that you select for protection. Select **Configure later** to select the Azure network per virtual machine. If you don't have a network, you need to create one. To create a network by using Azure Resource Manager, select **Create new**. Select a subnet if applicable, and then select **OK**. :::image type="content" source="./media/vmware-azure-enable-replication/enable-rep3.png" alt-text="Enable replication target window."::: 1. For **Virtual machines** > **Select virtual machines**, select each virtual machine that you want to replicate. You can only select virtual machines for which replication can be enabled. Then select **OK**. If you can't see or select any particular virtual machine, see [Source machine isn't listed in the Azure portal](vmware-azure-troubleshoot-replication.md#step-3-troubleshoot-source-machines-that-arent-available-for-replication) to resolve the issue. :::image type="content" source="./media/vmware-azure-enable-replication/enable-replication5.png" alt-text="Enable replication Select virtual machines window."::: 1. For **Properties** > **Configure properties**, select the account that the process server uses to automatically install the Site Recovery Mobility service on the VM. Also, choose the type of target managed disk to use for replication based on your data churn patterns. 1. By default, all the disks of a source VM are replicated. To exclude disks from replication, clear the **Include** check box for any disks that you don't want to replicate. Then select **OK**. You can set additional properties later. [Learn more](vmware-azure-exclude-disk.md) about excluding disks. :::image type="content" source="./media/vmware-azure-enable-replication/enable-replication6.png" alt-text="Enable replication configure properties window."::: 1. From **Replication settings** > **Configure replication settings**, verify that the correct replication policy is selected. You can modify replication policy settings at **Settings** > **Replication policies** > _policy name_ > **Edit Settings**. Changes you make to a policy also apply to replicating and new virtual machines. 1. If you want to gather virtual machines into a replication group, enable **Multi-VM consistency**. Specify a name for the group, and then select **OK**. > [!NOTE] > - Virtual machines in a replication group replicate together and have shared crash-consistent and app-consistent recovery points when they fail over. > - Gather VMs and physical servers together so that they mirror your workloads. Enabling multi-VM consistency can affect workload performance. Do this only if the virtual machines are running the same workload, and you need consistency. :::image type="content" source="./media/vmware-azure-enable-replication/enable-replication7.png" alt-text="Enable replication window."::: 1. Select **Enable Replication**. You can track the progress of the **Enable Protection** job at **Settings** > **Jobs** > **Site Recovery Jobs**. After the **Finalize Protection** job runs, the virtual machine is ready for failover. ## Monitor initial replication After "Enable replication" of the protected item is complete, Azure Site Recovery initiates replication (synonymous to synchronization) of data from the source machine to target region. During this period, replica of source disks are created. Only after completion of copying original disks, the delta changes are copied to the target region. The time taken to copy the original disks depends on multiple parameters such as: - Size of the source machine disks - Bandwidth available to transfer the data to Azure (You can use deployment planner to identify the optimal bandwidth required) - Process server resources like memory, free disk space, and CPU available to cache and process the data received from protected items (make sure the process server is [healthy](vmware-physical-azure-monitor-process-server.md#monitor-proactively)) To track the progress of initial replication, go to the recovery services vault in the Azure portal. Under replicated items, monitor the "Status" column value of the replicated item. The status shows the percentage completion of initial replication. When you hover over the Status, you see the "Total data transferred". When you select the status, a contextual page opens and displays the following parameters: - Last refreshed at - shows the latest time that the replication information for the whole machine is refreshed by the service. - Completed percentage - shows the percentage of initial replication completed for the VM. - Total data transferred - Amount of data transferred from VM to Azure. :::image type="content" source="media/vmware-azure-enable-replication/initial-replication-state.png" alt-text="state-of-replication." lightbox="media/vmware-azure-enable-replication/initial-replication-state.png"::: - Synchronization progress (to track details at a disk level) - State of replication - If replication isn't started yet, the status shows "In queue". During initial replication, the service replicates only three disks at a time. This mechanism avoids throttling at the process server. - After replication starts, the status shows "In progress". - After initial replication finishes, the status shows "Complete". - Site Recovery reads through the original disk, transfers data to Azure, and captures progress at a disk level. Note that, Site Recovery skips replication of the unoccupied size of the disk and adds it to the completed data. So, sum of data transferred across all disks might not add up to the "total data transferred" at the VM level. - When you select the information balloon against a disk, you see details on when the replication (synchronization) was triggered for the disk, data transferred to Azure in the last 15 minutes, and the last refreshed timestamp. This timestamp shows the latest time that Azure service receives information from the source machine. :::image type="content" source="media/vmware-azure-enable-replication/initial-replication-info-balloon.png" alt-text="initial-replication-info-balloon-details." lightbox="media/vmware-azure-enable-replication/initial-replication-info-balloon.png"::: - Health of each disk is displayed - If replication is slower than expected, the disk status shows warning. - If replication isn't progressing, the disk status shows critical. If the health is in critical or warning state, make sure that Replication Health of the machine and [Process Sever](vmware-physical-azure-monitor-process-server.md) are healthy. As soon as the enable replication job finishes, the replication progress is 0% and total data transferred is NA. When you select it, the data against each identified disk is "NA". This status indicates that the replication isn't started yet and Azure Site Recovery didn't receive the latest statistics. The progress refreshes every 30 minutes. > [!NOTE] > Make sure to update Configuration servers, scale-out process servers, and mobility agents to versions 9.36 or higher to ensure accurate progress is captured and sent to Site Recovery services. ## View and manage VM properties Next, verify the properties of the source virtual machine. Remember that the Azure VM name needs to conform with [Azure virtual machine requirements](vmware-physical-azure-support-matrix.md#replicated-machines). 1. Go to **Settings** > **Replicated items**, and then select the virtual machine. The **Essentials** page shows information about the VM's settings and status. 1. In **Properties**, view replication and failover information for the VM. 1. In **Compute and Network** > **Compute properties**, change multiple VM properties. :::image type="content" source="./media/vmware-azure-enable-replication/vmproperties.png" alt-text="Compute and network properties window."::: - **Azure VM name**: Modify the name to meet Azure requirements, if necessary. - **Target VM size or VM type**: The default VM size is based on parameters that include disk count, NIC count, CPU core count, memory, and available VM role sizes in the target Azure region. Azure Site Recovery picks the first available VM size that satisfies all the criteria. You can select a different VM size based on your needs at any time before failover. The VM disk size is also based on source disk size, and you can only change it after failover. Learn more about disk sizes and IOPS rates at [Scalability and performance targets for VM disks](/azure/virtual-machines/disks-scalability-targets). - **Resource group**: Select a [resource group](../azure-resource-manager/management/overview.md#resource-groups), from which a virtual machine becomes a part of a post failover. You can change this setting at any time before failover. After failover, if you migrate the virtual machine to a different resource group, the protection settings for that virtual machine break. - **Availability set**: Select an [availability set](/azure/virtual-machines/windows/tutorial-availability-sets) if your virtual machine needs to be a part of a post failover. When you select an availability set, keep the following information in mind: - Only availability sets that belong to the specified resource group are listed. - VMs that are on different virtual networks can't be a part of the same availability set. - Only virtual machines of the same size can be a part of an availability set. 1. Add information about the target network, subnet, and IP address that's assigned to the Azure VM. 1. In **Disks**, see the operating system and data disks on the VM that you replicate. ### Configure networks and IP addresses Set the target IP address: - If you don't provide an address, the failed over VM uses DHCP. - If you set an address that isn't available at failover, the failover doesn't work. - If the address is available in the test failover network, you can use the same target IP address for test failover. The size that you specify for the target virtual machine determines the number of network adapters: - If the number of network adapters on the source virtual machine is less than or equal to the number of adapters that the target VM's size allows, the target has the same number of adapters as the source. - If the number of adapters for the source virtual machine exceeds the number that the target VM's size allows, the target size maximum is used. For example, if a source virtual machine has two network adapters and the target VM's size supports four, the target virtual machine has two adapters. If the source VM has two adapters but the target size supports one, the target virtual machine has one adapter. - If the virtual machine has multiple network adapters, they all connect to the same network. Also, the first adapter in the list becomes the default network adapter in the Azure virtual machine. ### Azure Hybrid Benefit Microsoft Software Assurance customers can use Azure Hybrid Benefit to save on licensing costs for Windows Server computers that they migrate to Azure. The benefit also applies to Azure disaster recovery. If you're eligible, assign the benefit to the virtual machine that Site Recovery creates during a failover. 1. Go to the **Computer and Network properties** of the replicated virtual machine. 1. Answer when asked if you have a Windows Server license that makes you eligible for Azure Hybrid Benefit. 1. Confirm that you have an eligible Windows Server license with Software Assurance that you can use to apply the benefit to the VM that Site Recovery creates at failover. 1. Save the settings for the replicated virtual machine. [Learn more](https://azure.microsoft.com/pricing/hybrid-benefit/) about Azure Hybrid Benefit. ## Next steps After the virtual machine reaches a protected state, try a [failover](site-recovery-failover.md) to check whether your application appears in Azure. - [Learn more](site-recovery-manage-registration-and-protection.md) about how to clean registration and protection settings to disable replication. - [Learn more](vmware-azure-disaster-recovery-powershell.md) about how to automate replication for your virtual machines by using PowerShell.