SIRIS, ALTO, and NAS: Connecting a SIRIS to a VMware Hypervisor



This article explains how to connect a SIRIS to a VMware hypervisor.


  • Datto SIRIS


These instructions apply to virtual and physical SIRIS appliances to enable agentless backups, ESXi Virtualizations, and ESXi uploads. For Hyper-V instructions, see Connecting A SIRIS To A Hyper-V Hypervisor / Virtualization Offload To A Hyper-V Host.

System Requirements

Datto SIRIS supports hypervisor connections to the following paid versions of VMware vSphere:

  • VMware vSphere 5.5
  • VMware vSphere 6.0
  • VMware vSphere 6.5
  • VMware vSphere 6.7


To back up a virtual machine hosted on VMware vSphere, you must set up a connection to the hypervisor. This connection enables automatic screenshots and virtualization.

1. In the Datto device GUI, click Configure → Hypervisor Connections → Add Connection.

hyper1.pngFigure 1: Add Hypervisor Connections (click to enlarge)

2. Add a Connection Name and Server Address. The Hypervisor Type will default to ESX. Use this setting to create an ESXi connection.

  • Always enter the highest-level connection for the Server Address; the Datto will autodetect your ESXi environment. Use the IP address of the vCenter server that manages the host.
  • If you are using a clustered environment, use the IP/FQDN for either the vSphere Client or the web client.

hyper2.pngFigure 2: Hypervisor Connection Name (click to enlarge)

3. Fill in the fields for the Hypervisor Login, as shown in Figure 3.

  • The account that the Datto appliance uses to connect to the hypervisor must be one of the following types:
    • A Domain Administrator for the vCenter instance
    • A root account on the hypervisor

hyper3.pngFigure 3: Hypervisor Login (click to enlarge)

4. Specify your ESXi Hypervisor Options.

  • If you are connecting to a vCenter managed environment, you will be prompted for a Data Center, Cluster, Host Address, Offload Method (NFS/iSCSI), Datastore, and Network Adapter.
  • If you are connecting to a standalone environment, you will be prompted for an Offload Method (NFS/iSCSI), Datastore, and Network Adapter.
Note: if you choose to connect to the standalone host, you will have to configure a connection for each one you wish to back up agents from, use for screenshot offloading, or restore to.

Offload method considerations


  • Can easily migrate in case of disaster recovery after virtualization
  • No extra steps to set up the connection


  • You offload via RDM mapped drives. When using vMotion (external link), ESXi will move RDM mapped VMDKs normally. The RDM mapped VMDKs, however, are equivalent to symlinks.
  • iSCSI is more secure then NFS.
  • ISCSI requires setting up an extra vmKernel port.
Your Datto appliance will only display the Cluster and Datastore fields if they apply to the type of connection you are configuring.

hyper4.pngFigure 4: ESXi Hypervisor Options, vCenter Managed configuration shown (click to enlarge)

  • When adding a datastore, specify a location to store the virtual machine during ESXi virtualization and screenshot verification.
    • The location can be a different datastore than where the virtual SIRIS appliance virtual machine is located.
    • The datastore should have enough space to hold the .vswap file for each ESXi virtualization.
    • Each .vswap file is equal to the amount of memory allocated to the virtual machine.
  • When configuring a network adapter, specify the NIC on the SIRIS appliance that is attached to the same subnet as the iSCSI adapter on the ESXi host. The iSCSI traffic will travel over this NIC.
  • You use the iSCSI adapter on the ESXi host for ESXi virtualization.
    • For proper iSCSI connection and RDM creation, the adapter should be on the same subnet as one of the NICs on the SIRIS appliance.
    • If you use a software iSCSI adapter, then it should be bound to a VMkernel adapter on the same subnet as one of the NICs on the SIRIS appliance.

If you don't already have an iSCSI adapter set up on your ESXi host, see page 69 of vSphere (external link) for instructions.

Once you click Next, the Datto appliance will connect to the hypervisor and display your connections, as shown in Figure 5.

hyper5.pngFigure 5: Successful connection (click to enlarge)

You can now add pair VMs for backup using the System Backup Wizard.

Updating Connection Credentials 

If you need to update the hypervisor credentials for an existing connection, click the pencil icon on the right side of your hypervisor connection listing. The connection wizard will re-launch and allow you to make changes without having to re-boot or re-connect the hypervisor.

hyper6.pngFigure 6: Edit hypervisor connection (click to enlarge)

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