Support matrix for backup with the Microsoft Azure Recovery Services (MARS) agent
You can use the Azure Backup service to back up on-premises machines and apps and to back up Azure virtual machines (VMs). This article summarizes support settings and limitations when you use the Microsoft Azure Recovery Services (MARS) agent to back up machines.
The MARS agent
Azure Backup uses the MARS agent to back up data from on-premises machines and Azure VMs to a backup Recovery Services vault in Azure. The MARS agent can:
- Run on on-premises Windows machines so that they can back up directly to a backup Recovery Services vault in Azure.
- Run on Windows VMs so that they can back up directly to a vault.
- Run on Microsoft Azure Backup Server (MABS) or a System Center Data Protection Manager (DPM) server. In this scenario, machines and workloads back up to MABS or to the DPM server. The MARS agent then backs up this server to a vault in Azure.
Note
Azure Backup doesn't support automatic adjustment of clock for daylight savings time (DST). Modify the policy to ensure daylight savings is taken into account to prevent discrepancy between the actual time and scheduled backup time.
Your backup options depend on where the agent is installed. For more information, see Azure Backup architecture using the MARS agent. For information about MABS and DPM backup architecture, see Back up to DPM or MABS. Also see requirements for the backup architecture.
| Installation | Details |
|---|---|
| Download the latest MARS agent | You can download the latest version of the agent from the vault, or download it directly. |
| Install directly on a machine | You can install the MARS agent directly on an on-premises Windows server or on a Windows VM that's running any of the supported operating systems. |
| Install on a backup server | When you set up DPM or MABS to back up to Azure, you download and install the MARS agent on the server. You can install the agent on supported operating systems in the backup server support matrix. |
Note
By default, Azure VMs that are enabled for backup have an Azure Backup extension installation. This extension backs up the entire VM. You can install and run the MARS agent on an Azure VM alongside the extension if you want to back up specific folders and files, rather than the complete VM. When you run the MARS agent on an Azure VM, it backs up files or folders that are in temporary storage on the VM. Backups fail if the files or folders are removed from the temporary storage or if the temporary storage is removed.
Cache folder support
When you use the MARS agent to back up data, the agent takes a snapshot of the data and stores it in a local cache folder before it sends the data to Azure. The cache (scratch) folder has several requirements:
| Cache | Details |
|---|---|
| Size | Free space in the cache folder should be at least 5 to 10 percent of the overall size of your backup data. |
| Location | The cache folder must be locally stored on the machine that's being backed up, and it must be online. The cache folder shouldn't be on a network share, on removable media, or on an offline volume. |
| Folder | The cache folder shouldn't be encrypted on a deduplicated volume or in a folder that's compressed, that's sparse, or that has a reparse point. |
| Location changes | You can change the cache location by stopping the backup engine (net stop obengine) and copying the cache folder to a new drive. (Ensure the new drive has sufficient space.) Then update two registry entries under HKLM\SOFTWARE\Microsoft\Windows Azure Backup (Config/ScratchLocation and Config/CloudBackupProvider/ScratchLocation) to the new location and restart the engine. |
Networking and access support
The MARS agent requires access to Microsoft Entra ID, Azure Storage, and Azure Backup service endpoints. To obtain the public IP ranges, see the JSON file. Allow access to the IPs corresponding to Azure Backup (AzureBackup), Azure Storage (Storage), and Microsoft Entra ID (AzureActiveDirectory). Also, depending on your Windows version, network connectivity checks of the operating system will need access to www.msftconnecttest.com, or www.msftncsi.com.
If your machine has limited internet access, ensure that firewall, proxy, and network settings allow access to the following FQDNs and public IP addresses.
URL and IP access
FQDNs
*.microsoft.com*.windowsazure.com*.microsoftonline.com*.windows.net*.blob.core.windows.net*.queue.core.windows.net*.blob.storage.azure.net
If you are a US Government customer, ensure that you have access to the following URLs:
www.msftncsi.com*.microsoft.com*.windowsazure.us*.microsoftonline.us*.windows.net*.usgovcloudapi.net*.blob.core.windows.net*.queue.core.windows.net*.blob.storage.azure.net
Access to all of the URLs and IP addresses listed above uses the HTTPS protocol on port 443.
When backing up files and folders from Azure VMs using the MARS Agent, you also need to configure the Azure virtual network to allow access. If you use Network Security Groups (NSG), use the AzureBackup service tag to allow outbound access to Azure Backup. In addition to the Azure Backup tag, you also need to allow connectivity for authentication and data transfer by creating similar NSG rules for Microsoft Entra ID (AzureActiveDirectory) and Azure Storage (Storage).
To create a rule for the Azure Backup tag, follow these steps:
- In All Services, go to Network security groups and select the network security group.
- Select Outbound security rules under Settings.
- Select Add.
- Provide all required details for creating a new rule as described in security rule settings.
Ensure the options are set as below:- Destination is set to Service Tag.
- Destination service tag is set to AzureBackup.
- Select Add to save the newly created outbound security rule.
You can similarly create NSG outbound security rules for Azure Storage and Microsoft Entra ID. To learn more about service tags, see Virtual network service tags.
Azure ExpressRoute support
You can back up your data through Azure ExpressRoute by using public peering (available for old circuits). We don’t support Microsoft peering Backup over private peering.
To use public peering, ensure that the following domains and addresses have HTTPS access on port 443 to:
*.microsoft.com*.windowsazure.com*.microsoftonline.com*.windows.net*.blob.core.windows.net*.queue.core.windows.net*.blob.storage.azure.net
To use Microsoft peering, select the following services, regions, and relevant community values:
- Microsoft Entra ID (12076:5060)
- Azure region, according to the location of your Recovery Services vault
- Azure Storage, according to the location of your Recovery Services vault
Learn more about ExpressRoute routing requirements.
Note
Public peering is deprecated for new circuits.
Private Endpoint support
You can now use Private Endpoints to back up your data securely from servers to your Recovery Services vault. As Microsoft Entra ID can’t be accessed via private endpoints, you need to allow IPs and FQDNs required for Microsoft Entra ID for outbound access separately.
When you use the MARS agent to back up your on-premises resources, ensure that your on-premises network (containing your resources to be backed up) is peered with the Azure VNet that contains a private endpoint for the vault. You can then continue to install the MARS agent and configure backup. However, you must ensure all communication for backup happens through the peered network only.
If you remove private endpoints for the vault after a MARS agent has been registered to it, you'll need to re-register the container with the vault. You don't need to stop protection for them. For more information, see Private endpoints for Azure Backup.
Throttling support
| Feature | Details |
|---|---|
| Bandwidth control | Supported. In the MARS agent, use Change Properties to adjust bandwidth. |
| Network throttling | Not available for backed-up machines that run Windows Server 2008 R2, Windows Server 2008 SP2, or Windows 7. |
Supported operating systems
Note
The MARS agent does not support Windows Server Core SKUs.
You can use the MARS agent to back up directly to Azure on the operating systems listed below that run on:
- On-premises Windows or Windows Servers
- Azure VMs running Windows
The operating systems must be 64 bit and should be running the latest services packs and updates. The following table summarizes these operating systems:
| Operating system | Files/folders | System state | Software/Module requirements |
|---|---|---|---|
| Windows 11 (Enterprise, Pro, Home, IoT Enterprise) | Yes | No | Check the corresponding server version for software/module requirements |
| Windows 10 (Enterprise, Pro, Home, IoT Enterprise) | Yes | No | Check the corresponding server version for software/module requirements |
| Windows 8.1 (Enterprise, Pro) | Yes | No | Check the corresponding server version for software/module requirements |
| Windows 8 (Enterprise, Pro) | Yes | No | Check the corresponding server version for software/module requirements |
| Windows Server 2022 (Standard, Datacenter, Essentials, Server IoT) | Yes | Yes | Check the corresponding server version for software/module requirements |
| Windows Server 2019 (Standard, Datacenter, Essentials, Server IoT) | Yes | Yes | - .NET 4.5 - Windows PowerShell - Latest Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 |
| Windows Server 2016 (Standard, Datacenter, Essentials) | Yes | Yes | - .NET 4.5 - Windows PowerShell - Latest Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 |
| Windows Storage Server 2016/2012 R2/2012 (Standard, Workgroup) | Yes | No | - .NET 4.5 - Windows PowerShell - Latest Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 |
| Windows Server 2012 R2 (Standard, Datacenter, Foundation, Essentials) | Yes | Yes | - .NET 4.5 - Windows PowerShell - Latest Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 |
| Windows Server 2012 (Standard, Datacenter, Foundation) | Yes | Yes | - .NET 4.5 -Windows PowerShell - Latest Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 - Deployment Image Servicing and Management (DISM.exe) |
For more information, see Supported MABS and DPM operating systems.
Operating Systems at end of support
The following operating systems are at the end of support and it's strongly recommended to upgrade the operating system to continue to stay protected.
If existing commitments prevent upgrading the operating system, consider migrating the Windows servers to Azure VMs and leverage Azure VM backups to continue staying protected. Visit the migration page here for more information about migrating your Windows server.
For on-premises or hosted environments, where you can't upgrade the operating system or migrate to Azure, activate Extended Security Updates for the machines to continue staying protected and supported. Notice that only specific editions are eligible for Extended Security Updates. Visit the FAQ page to learn more.
| Operating system | Files/folders | System state | Software/Module requirements |
|---|---|---|---|
| Windows 7 (Ultimate, Enterprise, Pro, Home Premium/Basic, Starter) | Yes | No | Check the corresponding server version for software/module requirements |
| Windows Server 2008 R2 (Standard, Enterprise, Datacenter, Foundation) | Yes | Yes | - .NET 3.5, .NET 4.5 - Windows PowerShell - Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 - Deployment Image Servicing and Management (DISM.exe) |
| Windows Server 2008 SP2 (Standard, Datacenter, Foundation) | Yes | No | - .NET 3.5, .NET 4.5 - Windows PowerShell - Compatible Microsoft VC++ Redistributable - Microsoft Management Console (MMC) 3.0 - Deployment Image Servicing and Management (DISM.exe) - Virtual Server 2005 base + KB KB948515 |
Backup limits
Size limits
Azure Backup limits the size of a file or folder data source that can be backed up. The items that you back up from a single volume can't exceed the sizes summarized in this table:
| Operating system | Size limit |
|---|---|
| Windows Server 2012 or later | 54,400 GB |
| Windows Server 2008 R2 SP1 | 1,700 GB |
| Windows Server 2008 SP2 | 1,700 GB |
| Windows 8 or later | 54,400 GB |
| Windows 7 | 1,700 GB |
Retention limits
The following are the retention durations that can be set for the different recovery points:
| Recovery point | Minimum | Maximum |
|---|---|---|
| Daily recovery point | 7 days | 9999 days |
| Weekly recovery point | 4 weeks | 5163 weeks |
| Monthly recovery point | 3 months | 1188 months |
| Yearly recovery point | 1 year | 99 years |
Other limitations
- MARS doesn't support protection of multiple machines with the same name to a single vault.
Supported file types for backup
| Type | Support |
|---|---|
| Encrypted* | Supported. |
| Compressed | Supported. |
| Sparse | Supported. |
| Compressed and sparse | Supported. |
| Hard links | Not supported. Skipped. |
| Reparse point | Not supported. Skipped. |
| Encrypted and sparse | Not supported. Skipped. |
| Compressed stream | Not supported. Skipped. |
| Sparse stream | Not supported. Skipped. |
| OneDrive (synced files are sparse streams) | Not supported. |
| Folders with DFS Replication enabled | Not supported. |
* Ensure that the MARS agent has access to the required certificates to access the encrypted files. Inaccessible files will be skipped.
Supported drives or volumes for backup
| Drive/volume | Support | Details |
|---|---|---|
| Read-only volumes | Not supported | Volume Copy Shadow Service (VSS) works only if the volume is writable. |
| Offline volumes | Not supported | VSS works only if the volume is online. |
| Network share | Not supported | The volume must be local on the server. |
| BitLocker-locked volumes | Not supported | The volume must be unlocked before the backup starts. |
| File system identification | Not supported | Only NTFS is supported. |
| Removable media | Not supported | All backup item sources must have a fixed status. |
| Deduplicated drives | Supported | Azure Backup converts deduplicated data to normal data. It optimizes, encrypts, stores, and sends the data to the vault. |
Support for initial offline backup
Azure Backup supports offline seeding to transfer initial backup data to Azure by using disks. This support is helpful if your initial backup is likely to be in the size range of terabytes (TBs). Offline backup is supported for:
- Direct backup of files and folders on on-premises machines that are running the MARS agent.
- Backup of workloads and files from a DPM server or MABS.
Offline backup can't be used for system state files.
Support for data restoration
By using the Instant Restore feature of Azure Backup, you can restore data before it's copied to the vault. The machine you're backing up must be running .NET Framework 4.5.2 or higher.
Backups can't be restored to a target machine that's running an earlier version of the operating system. For example, a backup taken from a computer that's running Windows 7 can be restored on Windows 8 or later. But a backup taken from a computer that's running Windows 8 can't be restored on a computer that's running Windows 7.
Previous MARS agent versions
The following table lists the previous versions of the agent with their download links. We recommend you to upgrade the agent version to the latest, so you can leverage the latest features and optimal performance.
| Versions | KB Articles |
|---|---|
| 2.0.9145.0 | Not available |
| 2.0.9151.0 | Not available |
| 2.0.9153.0 | Not available |
| 2.0.9162.0 | Not available |
| 2.0.9169.0 | 4515971 |
| 2.0.9170.0 | Not available |
| 2.0.9173.0 | 4538314 |
| 2.0.9177.0 | Not available |
| 2.0.9181.0 | Not available |
| 2.0.9190.0 | 4575948 |
| 2.0.9195.0 | 4582474 |
| 2.0.9197.0 | 4589598 |
| 2.0.9207.0 | 5001305 |
Note
MARS agent versions with minor reliability and performance improvements don't have a KB article.
Next steps
- Learn more about backup architecture that uses the MARS agent.
- Learn what's supported when you run the MARS agent on MABS or a DPM server.
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