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Writing Replicated VMFS LUN Data To Tape

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Valued Contributor

Writing Replicated VMFS LUN Data To Tape

We have a situation with a customer whereby snapshots are used for daily & weekly backups, and replicas are sent to a DR box.

There is a requirement to copy replicated data from the arrays onto tape for longer-term retention (up to 7 years). Cloning a replica and presenting this to a backup server at the DR site is the easy part, however I was wondering whether anyone has any suggestions about how best to write replicated VMFS volumes to tape? Considering that the backup server will invariably be a Windows OS and trying to minimise manual intervention at the DR site...

Currently, we have a couple of ideas:

     1. Host-based tools to mount the VMFS volume on a Windows/Linux box, then have the backup application take a backup of the mounted directory.

     2. Have an ESXi host at the DR site, present & mount the cloned replica and have the backup application take a backup of the VMs using VADP

Has anyone done this before using either approach outlined above, or a different way? If so, any thoughts?



Occasional Visitor

Re: Writing replicated VMFS LUN data to tape

Hi Ben,

We currently have a similar issue and are considering the second approach. I see your question was from April, did you make any progress since then?

My supplier is looking at this as well so I will post if I find anything out.



Re: Writing replicated VMFS LUN data to tape

Hi Gary/Ben,

Been looking into this.

Windows cannot read VMFS thus mounting a VMware datastore (or its clone) to a Windows based backup server does not allow the backup software to back the files to its target.

There is an open-source VMFS driver that uses Java and WEBDAV however, that would allow us to do this and it has been documented here with clear instructions on how it can be achieved. 

Access a VMFS drive under windows |

Although it is possible, its certainly not elegant and will also require integration with Powershell scripts  to clone from a replica, mount them to Windows and then more scripting to automate the driver bits.

When looking at your mainstream backups products like BackupExec, they use a different process based on VADP to backup VM data from datastores. When using SAN direct backups, the backup server needs access to the LIVE datastores, thus I don't think it works when mapping a clone of a replica instead of the live volume to the Backup Server, but need to test this a little more.

The process it uses is as follows:

  1. Backup Exec backup job starts
  2. Backup Exec tells VMware to create a snapshot of VMDK through vCenter
  3. vCenter creates and mounts the snapshot to the datacenter and it now becomes the "active" snapshot (virtual machine is now running from that snaphsot)
  4. Backup Exec then gets the ESX host and guest virtual machine information from vCenter it needs to access or backup
  5. Backup Exec opens a connection with the ESX to ask for the virtual machine metadata
  6. Using vStorage APIs, Backup Exec then opens a direct data connection to the “unknown” SAN volumes and the virtual machine data is offloaded directly to the media server for backup
    1. “Extracting the Backup Data from the Target Virtual Machine”
    2. “Deleting the Temporary Snapshot”
  7. Once the backup completes, Backup Exec disconnects from the ESX host and vCenter
  8. Backup Exec runs a verify (by default) of the data backed up
  9. Backup job completes.

Taken from the Symantec forum reference

Life would have been easier if BackupExec could simply read the VMFS datastore (with its own VMFS driver or using the Open source one), then just backs up those files to the target. (Come on Symantec)

Occasional Visitor

Re: Writing replicated VMFS LUN data to tape

Hello Ben/Amirul,

I believe the VMFS driver wouldn't work for us anyway. The driver supports VMFS version 3. Because we have created the data stores from scratch under vSphere 5.0 the data stores are formatted as VMFS 5.54. So I expect this wouldn't work.

Is there no backup vendor which supports VMFS? Or does VMWare keep this to themselves in some way.

Occasional Advisor

Re: Writing replicated VMFS LUN data to tape

Ben - Have you looked at Veeam or Unitrends?  I know adding another backup software adds more complexity but these packages can backup VMware datastores.

Just a suggestion.

Re: Writing Replicated VMFS LUN Data To Tape

Veeam Backup and Recovery v8 beta introduces the ability to use the Veeam data mover proxy server as a tape library target. You could have the main Veeam server at HQ and a proxy at DR which has the library attached. Using Veeam to replicate the data to a repository at DR you could then subsequently have Veeam take that local DR copy and write it out to tape. I think this is the simplest solution to your problem, although I am sure there are other ways. The downside to this of course is that you have to use Veeam for the replication as opposed to the snapshot replication. In the future, it is possible that Veeam "could" be able to work with the Nimble snapshots directly, similar to what they offer with NetApp and HP now...

Virtualization Lead Architect
BEMA Information Technologies
Occasional Visitor

Re: Writing Replicated VMFS LUN Data To Tape

Thanks Steve, good ideas.