Getting started with agentless backups

Topic

This article describes system requirements for agentless backups to a Datto appliance.

Environment

  • Datto SIRIS
  • Agentless backups

Description

System requirements

Virtual OS
  • Windows XP (note: Microsoft no longer issues keys for Windows XP: you may not be able to re-activate installations that use OEM keys)
  • Windows Server 2003 (note: Microsoft no longer issues keys for Windows Server 2003: you may not be able to re-activate installations that use OEM keys)
  • Windows Vista
  • Windows Server 2008 / R2
    • Includes Windows Small Business Server 2011
  • Windows 7
  • Windows 8 / 8.1
  • Windows 10
  • Windows Server 2012 / R2
  • Windows Server 2016
  • Windows Server 2019

Linux OS Compatability

Linux OS compatibility is the same as the Datto Linux Agent. Hardware Independent Restore (HIR) is not supported for EFI Linux whether agentless of agent based. See Getting started with the Datto Linux Agent for details and a list of supported Linux distributions.

For compatibility information about operating systems not listed here, see the Warnings section of this article.

Virtual hardware requirements
  • Target virtual machines must run virtual machine hardware version 7;or higher. See VMware's Virtual machine hardware versions (external link) article for help determining if your virtual machine's hardware profile is up-to-date.
  • Windows backups: VMware Tools must be present on the target VM.
  • Linux backups: install open-vm-tools. This package includes the necessary VMware Snapshot Provider service.
Network

Communication between the virtual environment and the Datto appliance requires the following ports:

On both the Host and the Datto Appliance:

  • TCP 443 (HTTPS)
  • TCP 902 (Network File Copy)

On the Datto Appliance:

  • TCP 10443 (HTTPS)
  • TCP 9000-9010 (Failover ports)
  • TCP 3260 (iSCSI)
  • TCP/UDP 111 (NFS)
  • TCP/UDP 2049 (NFS)
  • TCP 22 (SSH)
  • TCP 9080 (IO Filter)
  • TCP 8805

In addition, see Unified Backup Networking & Bandwidth Requirements article for general networking requirements.

Hypervisor

Agentless backups run on physical SIRIS and Virtual SIRIS powered by vSphere versions 6.0, 6.5, 6.7, 7.0, and 8.0.

  • vSphere Essentials
  • vSphere Essentials Plus
  • vSphere Standard
  • vSphere Enterprise
  • vSphere Enterprise Plus
  • Evaluation licenses and VMware vCloud Service Provider are unsupported.
  • Hyper-V not currently supported for agentless backups

.

Overview

Physical and virtual Datto SIRIS appliances can take agentless backups of virtual machines running VMware vSphere. Agentless backups use the host hypervisor's capabilities to take a snapshot of the production VM (even when shut down).

NOTE  The agentless backup solution is not available for Datto ALTO or Datto NAS appliances.

You do not need to install a backup agent on the target machine for agentless backups to communicate with the Datto appliance. See the Backup Process section of this article for a technical overview of how agentless backups work.

Benefits

  • Communication from VM targets to Datto appliances is quicker and easier.
  • Backups, done through VMware's data storage API (VADP) (external link), are more efficient.
  • Agentless backups work on both Windows and Linux virtual machines.
  • You can run a backup even when a VM is powered off.
  • Other common SIRIS functions remain the same.
  • If you prefer, you can still back up your machines using an agent-based solution. (see this article for crucial agent-based deployment considerations).

Limitations

SIRIS Virtual and agentless backups do not support the free version of vSphere.

  • Agentless backups do not work on encrypted VMs
  • Agentless backup support is unavailable for:
    • spanned volumes
    • ESXi shared volumes
    • multiple volumes using the same GUID
    • systems using Logical Volume Management (LVM)
    • backup of deduplicated volumes is untested and may produce inconsistent results.
    • file restore of deduplicated volumes is not possible. Restoration of deduplicated volumes through virtualization, Direct Restore, or Bare Metal Restore, is not supported.
    • volumes formatted using Microsoft's ReFS.
    • Windows systems that contain volumes that use Dynamic Disk Technology (These systems may have issues regardless of whether the Dynamic Disk volumes are included in the backup or not).
    • Backup of User Profile Disks used by the Remote Desktop Service is unsupported. Remote Desktop Service (external link). These volumes should be excluded from backups.

Universal VM Backup may be a viable alternative in the above scenarios.

Agentless backups from a physical device (and failover for Virtual SIRIS) operate through the Network Block Driver Transport Method, which restricts their operating speed to a maximum of 40% of the management network interface speed.

Backup process

Unlike agent-based backups, which are VSS-dependent, in an agentless backup, the Datto appliance interacts directly with your hypervisor to snapshot and back up a virtual machine. It does so by taking the following steps:

  1. The Datto appliance uses the hypervisor connection to connect to the vSphere environment.
  2. The VMware snapshot provider (part of VMware tools) takes a snapshot of the VM.
    The first two steps also occur when the Datto pairs with the target VM.
  3. If the Datto device is a virtual appliance, it can use HotAdd (through vddk-fuse) to directly attach the VMDK from the VMware snapshot to itself. HotAdd transfers the backup data over the vSphere management network. As a failover, or if the Datto device is a physical appliance, the Datto appliance connects to the VMDK from the VMware snapshot using the Network Block Device (NBD) protocol. With this type of connection, the VM network transfers the data.
  4. The Datto appliance uses libguestfs to analyze the disk image to get information about the disk structure and the file system(s) on it.
  5. The appliance transfers the backup data from the VMware snapshot of the VMDK to itself, and takes a ZFS snapshot of the disk images in the live dataset, just like an agent-based backup.

Warnings

IMPORTANT  Operating systems that are not compatible with Datto's standard agentless backup method will be protected by the Universal VM Backup solution. Universal VM Backup is a limited agentless solution that allows you to restore via Export Image or Virtualize via hypervisor methods only.

If you add a new volume to a protected agentless system after it has already been backed up by the Datto appliance, you must reboot the protected host before the new volume can begin backups.

Installation

Before you can take an agentless backup, you need to connect the Datto appliance to your hypervisor. For hypervisor connection steps, see the article Connecting A Datto Appliance To A VMware Hypervisor.

To pair a virtual machine for backup on the Datto appliance, see the Pairing a Target System for Agentless Backups article.

The host hypervisor and protected virtual machines must be in a healthy, stable state. For more information, see Agentless Backups: Best Practices.

Additional Resources