Windows Pre-Deployment And Ongoing Server Requirements



How do I ensure my Windows environment is properly configured for the Datto backup solution?


  • Windows
  • Windows Server


Supported operating systems

  • Windows 10
  • Windows 8.1
  • Windows 7
  • Windows Vista
  • Windows XP
  • Windows 2000 (ShadowSnap agent only)
  • Windows Server 2016
  • Windows Server 2012/R2
  • Windows Server 2011
  • Windows Server 2008/R2
  • Windows Server 2003
Software RAID is supported for backups, virtualizations, and file restores, but is incompatible with Bare Metal Restore
Scope of support for these operating systems includes 32-bit and 64-bit versions.

Dual-boot environments

Any of the above Windows installations running on Apple hardware via Boot Camp are supported for backup, virtualization, image export, and file restore. Due to dual-boot environment limitations, Bare Metal Restore is not supported, and only the Windows partition on Boot Camp installations will be backed up.

Supported disk volume types

  • The Datto Windows Agent, ShadowSnap Agent, and agentless backup solutions are capable of restoring deduplicated volumes through virtualization, Direct Restore, and Bare Metal Restore. However, file restores of deduplicated volumes will not be possible.
  • Basic volumes and disks
    It is possible to back up Windows dynamic disks, but if a dynamic disk expands, the next backup following the expansion will be a differential merge backup. Frequent differential merges may compromise your ability to keep a backup schedule at pre-defined intervals, and will greatly increase the window during which system resources are consumed by the backup agent.
  • NTFS Filesystems
  • Hardware and software-based arrays
  • Any size disk drive, including disks larger than 2TB in size
  • Virtual & physical disks

The Datto solution can back up multiple types of disk sector schemes. The process writes an image-based backup to a file which is 512 bytes per physical sector. While rare, certain software that relies on advanced formats (such as 4K) may have issues with the sector size change. Datto recommends performing regular DR tests to ensure that all required applications function as expected in our virtualized environments.

Minimum resource requirements

A minimum of 1 GB of free RAM is recommended for the backup agent. If the agent is reporting errors with less than 1 GB of RAM available, performance tuning or additional resources may be required. 

Available space on protected volumes

Datto recommends maintaining at least 30% free space per protected volume. A minimum of 20% free space per protected volume must always be available on the production machine.

Volume utilization

  • 0-70% of volume: utilization is good
    Expect normal function.

  • 71-80% of volume: warning
    Utilization is outside optimal limits. Monitor the volume growth and look at cleaning up unnecessary files and moving non-essential data to other storage. Backups may begin to fail.

  • 81-100% of volume: critical
    Volume is becoming critical. Snapshots may sometimes fail, and disk queue lengths will increase. Create space.

Web Browser

The Datto web interface functions best with Mozilla Firefox or Google Chrome browsers. Using Internet Explorer may compromise functionality.

Setting backup schedules and initial configuration

  • Before setting a backup schedule, discuss with your client how far back you would ever need to go to retrieve data. Set the expectations with them and provide a schedule accordingly. Set the local data retention policies based on these conversations and expectations. Remember that long-running retention policies will require more disk space, and should be considered when sizing an appliance.

  • Consider the server’s application. A file server may need multiple backups during business hours, as files are in constant change. A terminal server simply housing configurations, however, may not require as many backups per day, as there is little to no change provided. Like any other service on a server, backups consume resources and take disk input / output. Consider this when setting a schedule.

  • The size of your server's backups can grow if you use Distributed File System (DFS) in your environment. See How Distributed File System (DFS) Interacts with the Datto Solution for more information.

  • Before taking the first backup, make sure that any volumes that you do not want to back up are excluded in the advanced options tab. Remember that backups may be attempted on any additional drives attached to the machine (USB drives, additional storage drives, etc.).


 Follow these tips to get your server in shape for smooth backups:

Hardware Health

Run chkdsk to be sure that all RAIDs and individual disks report back as healthy. Perform necessary disk repairs before the deployment of any backup agent. Failure to do so may result in backing up corrupted systems and restoration failures.

Disk Defragmentation

While Datto can perform backups that are running disk defragmentation, be aware that this rearranges data at a block level, and larger backups will consequently result. Run a disk defragmentation before deployment of the agent. VSS-aware disk defragmentation programs may allow for smaller backups, but this would be left to your own discretion.

Windows updates

Download Windows updates, service packs, and any other Microsoft provided updates. After installing these updates, reboot the server. When scheduling your deployment, remember that the 2nd Tuesday of every month is Microsoft's "patch Tuesday."

Virus scan

Run a virus scan before you deploy the Datto Backup Software agent.

Event Viewer

Check the target's system and application logs to see if there are any VSS or hardware errors. Resolve any errors before attempting to install the agent.


Check for SQL maintenance jobs that may be taking place, as they are a separate backup solution and may cause conflicts. To avoid very large incremental backups, Datto recommends having SQL maintenance jobs saved to a partition unprotected by the Datto device. Otherwise, the local Datto may fill up, causing it to not sync to the Cloud properly. Best Practices for SQL servers can be found here.


Since Exchange Servers are essentially database servers with mail stores in EDB (Exchange Database Format), Datto recommends the same procedures for maintenance jobs as SQL (see above SQL recommendation). Make sure that the Exchange writers are enabled on your operating system. Also, check for additional enabled archiving tools (such as auto-archiving) that may cause larger incremental changes.

  • For Exchange 2010 and 2013, Datto recommends that you enable circular logging.
  • For earlier versions, VSS backups will truncate logs upon completion and circular logging can be disabled.


Datto recommends that hypervisors have their datastores isolated on a separate partition, and that the non-datastore volumes be backed up by the Datto Backup Software agent. Servers that reside on the datastore should be backed up individually to allow for more granular recovery and restore efforts. Best practices for backing up hypervisors can be found here.


Due to an incompatibility between the Datto backup software and Cluster Shared Volumes (CSVs), Datto backup software does not support backing up Hyper-V hosts that are members of a failover cluster. Datto Backup Software also does not support backing up any other OS that has access to a CSV. However, we can support backing up a guest VM running on a Hyper-V failover cluster, as long as the guest OS itself does not access a CSV.


ShadowSnap and ShadowProtect do not support the use of proxy servers on the network. Agents must check in to StorageCraft to verify their license monthly.


Due to their mobile nature, Datto does not endorse or support backing up laptops. laptops must be inside the LAN, and not on a wireless network, to perform backups in a timely manner. Attempts to back up laptops are at your own discretion.

Datto Windows Agent (DWA)

Firewall rules

  • The protected machine must have Internet access, and be able to reach, for the initial installation of the Datto Windows Agent.
  • From protected machine to Datto appliance: Port 3260 (for iSCSI), 3262 (for Mercury), UDP 139, and TCP 25568 must be open in both directions.
  • The Datto Windows Agent uses Mercury as its primary transport method; however, if this fails, backups are intended to fall back to iSCSI.
  • From Datto appliance to internet: ports 22, 80, 123, 443 must be open outbound to, at minimum, the addresses specified in this article: Datto IP Ranges.
  • You may need additional addresses for the off-site syncing continuity. See Datto Networking Requirements for local and offsite networking requirements and best practices.

Antivirus exceptions

  • Set service-level exceptions for the Datto Backup Agent and Datto Provider services. 
  • Set an application-level exception for the Datto Windows Agent (DattoBackupAgent.exe).
  • Whitelist the following installation path: 
    %SYSTEMROOT%\Program Files\Datto\Datto Windows Agent.
  • Verify that no other backup software is installed on the machine.

Additional resources

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