SAN-Direct Backups - Protecting VMs on a SAN (What is required?)


If you are using a Recovery-Series appliance, you have the option to protect the VMware Virtual Disks that are on a SAN (UEB/UB uses HotAdd Transport). This can be done over iSCSI or Fibre Chanel. For best performance, you should use a dedicated connection between the SAN and the Unitrends system (or it should be a closed network that is separate from the users).
The following requirements must first be met:
Your Unitrends Recovery-Series Appliance should be running the latest version of the RecoveryOS (version 8.2 or newer) and the Guest VMs to protect must be running on licensed ESXi hosts running VMware vSphere version 5.1, 5.5, 6.0, or 6.5 with the following storage configurations:

  • a vCenter Server is required to be registered to the unitrends Appliance.
  • Each ESXi host should also be added per best practices.  
  • SAN storage mounted on the ESX server as a VMFS data store.
    ​​​ or SAN storage mounted directly by the ESX guest as a Virtual (not Physical) RDM disk.
  • FC Connections must be single path or Active/Active ALUA.  Multi-Path is not supported.  
  • For non-VAAI storage arrays, the ESX host may perform certain operations on the datastore
    while the SAN-direct backup is running, causing a SCSI reservation conflict. In this case, the
    backup will continue over the network instead of the SAN, which increases both backup time
    and network traffic on the LAN. To reduce the probability of reservation conflicts, follow
    VMware’s recommendations in the article Frequently Asked Questions for vStorage APIs for
    Array Integration (1021976)



To configure a Recovery-Series appliance for SAN-direct backups for Fiber Channel

The only configuration effort required is to ensure the SAN is compatible and ensure the Unitrends WWPN is provided and provisioned on required SAN LUNs that VMWare backups will occur for.  With Unitrends use of VDDK 5.5 or higher and since release 9.0, the vprotect engine will determine compatible SAN paths from VMWare's own configuration, and VMWare will permit the use of that path automatically.  Other than proper SAN and VMWare provisioning, no Unitrends UI configuration is required.  

To identify the WWPN of your FC adapter in the Unitrends Appliance, see this KB.  ​

To Configure the Recovery-Series appliance for SAN-direct backups using iSCSI

  1. Verify that the VMware SAN-direct requirements have been met.
  2. Physically connect the Unitrends Recovery-Series appliance to the VLAN used for iSCSI using a dedicated network adapter. 
    • Typically a 10G connection is used (note, on 1Gbit, SAN Direct and NBDSSL will have no perceivable performance difference unless the reason to use SAN Direct is to avoid network saturation.)  
    • iSCSI IPs and other production IPs should not share the same VLAN.  
    • Production LANs should not be able to route to iSCSI Networks through gateways.  
  3. Log in to the backup system and select Configure > Appliances > Select the local appliance > edit
User-added image​​​​​​​
  • Complete the fields for iSCSI initiator and LUN selection for each LUN a VM resides in that requires protection.


IMPORTANT!   If vProtect cannot directly access the SAN, the backup runs using the network connection, moving the guest’s data from the external SAN through the ESX file system to the backup system. If using network bandwidth is a problem during certain hours, schedule your backups accordingly.  This decision is macde by VMWare's protocols, not by unitrends.   If SAN is configured but backups continue to use NBDSSL protocols, your SAN vendor or VMWare support or both may be asked to be engaged by Unitrends Support for further diagnosis.  Unitrends cannot manage or configure your SAN or VMWare host directly, but we will be happy to participate in your vendor support calls to facilitate speed of resolution.    
To check whether the backup ran using the SAN-direct method, double-click the backup in the Status window or on the Backups report to view associated details. Look for the following in the Raw Output in the vProtect Messages section:

  • using transport method san: The SAN-direct connection was used for the backup.
  • using transport method nbd (or nbdssl): The regular network connection was used for the backup.

This information is located in the “VMware SAN-direct backups” section of the Unitrends Administrators Guide.:

Have more questions?

Contact us

Was this article helpful?
0 out of 0 found this helpful

Provide feedback for the Documentation team!

Browse this section