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Using VSS

The Microsoft Volume Shadow Copy Service (VSS) enables application-consistent snapshots on volumes and specific applications used by Microsoft Windows. To enable Microsoft application consistent snapshots with the StorONE system, the StorONE VSS module must be installed on all Windows hosts or cluster members.

In order for Microsoft Application consistent snapshots to be enabled:

1) Only block-based volumes are supported for Microsoft Application consistent snapshots.  These can be directly mapped from the host to storage, or the volumes must otherwise appear as a drive letter on the host.  Network mapped shares cannot be used for Microsoft VSS snapshots with StorONE at this time.

2) The Microsoft application must be VSS capable (MS SQL, MS Exchange, MS Sharepoint etc)

3) The StorONE VSS application must be installed on each Microsoft host where application consistent snapshots are required.  For Microsoft clusters, the VSS application will need to be installed on each individual cluster member.

The StorONE VSS module currently supports block-based volumes (Fibre Channel or iSCSI directly mapped to a Windows host (VM or physical), or volumes configured as virtual disks through a hypervisor to a virtual machine. Volumes used as virtual disks can be block volumes or filesystem-based volumes (NFS).

Installing the StorONE VSS plugin on Microsoft Windows

Download the latest StorONE VSS installer .MSI file from the StorONE landing page. In a browser, go to the DNS name or IP address of either of the StorONE controller nodes.

Click StorONE VSS Installer to download the MSI installer. Run the installation on all Windows machines (physical or virtual) that use the StorONE volume that you want to enable VSS snapshots on.

After the installation finishes, two services are added to the Windows host: S1VssHardwareProvider and S1VssService:

The StorONE VSS hardware provider is named "S1VssHadwareProvider".  This service should be a manual start as it is only called and runs when Microsoft VSS snapshots are being taken.

When a Microsoft Application consistent snapshot is initiated by the StorONE system, the appliance contacts the VSS provider on the Windows machines on port 18222. In order for application consistent snapshots to work properly, make sure that this port is open for requests from the management IP on both StorONE controller nodes.  Microsoft Application consistent snapshots can be scheduled or manually triggered via the StorONE UI.

StorONE system configuration

In the StorONE graphical user interface (GUI), there are two steps required to enable Microsoft Application consistent snapshots:

Step 1: Enable VSS for the required volume

Step 2: Configure a Snapshot

Step 1: Enable VSS for the required volume

In the GUI go to Applications 🡪 Snapshots, and click the VSS button:

Enter the application and volume that the Windows machine is using, and add the IP addresses of all Windows machines using the volume.

If the volume is a block volume (iSCSI or Fibre Channel) directly mapped to the Windows hosts, make sure to check the Direct Mapping checkbox. 

If the volume is an NFS filesystem volume or a block volume used as a datastore hosting virtual disks for the Windows hosts, do not check the Direct Mapping checkbox.

On the Applications 🡪 Snapshots page, you can manually take a one-time snapshot by clicking the Take button, or by clicking Schedule to schedule recurring snapshots. In both cases, check the Enable Vss box.

When a VSS-enabled snapshot is initiated, the StorONE system will communicate with the VSS services on the Windows machines to coordinate an application-consistent snapshot.

Using the CLI

To manually take a Microsoft Application consistent snapshot using the CLI, use the --vss argument:

Troubleshooting

In some cases, the VSS backup fails with error 8194: Access Denied. This is caused when the Windows NETWORK SERVICE predefined local user does not have sufficient access permissions on the machine backup is executed.

To fix this issue, please add the relevant permissions - 

  • Open the Windows Start Menu, then run dcomcnfg tool
  • Expand the path Console Root 🡪 Component Services 🡪 Computers
  • Right-click on My Computer, then select Properties
  • In the My Computer Properties dialog box, switch to the COM Security tab

VSS1.png

  • In the Access Permission dialog box, click Add and enter NETWROK SERVICE. 

VSS2_.png

  • To make sure the spelling is correct click Check Names button

vss3.png

  • After adding the Network Service make sure the Local Access permissions exist for this object

VSS4.png

Click OK to finish the configuration.

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