Microsoft Virtualization Discussions

SnapInfo Lun on SMHV



I am on SMHV installation for one my customer, and it's the first time i install a SMHV.

How sizing the snapinfo lun ?

I have two hyper-v host (not in cluster) to backup.

On each hyper-v i have 4 vm.

Each vm take about 30go on my two VM lun ...




We don't have any best practice recommendation for the SnapInfo LUN.

Each Hyper-V VM backup's metadata entry stored in the snapinfo folder takes atmost 50 KB of space to store the metadata of one backup.

You can provision your storage based on this information.

Also we recommend SnapInfo LUN on a separate volume and is always preferable keeping in mind of the 255 snapshot count on a volume.


Additional info about SnapInfo snapshot for your reference from SMHV release notes.

After creating a dataset backup, SnapManager for Hyper-V creates a snapshot of the SnapInfo LUN.

SnapInfo snapshots are not deleted if the backup is deleted. SnapInfo snapshots have a different retention

policy. By default, SnapManager for Hyper-V retains 30 SnapInfo LUN snapshots and deletes the older

ones when the SnapInfo snapshot count exceeds 30.

You can confgiure the number of SnapInfo snapshots you want to retain for each Hyper-V host using

the following registry key:

For stand-alone Hyper-V hosts:

key: HKLM\SOFTWARE\NetApp\SnapManager for Hyper-V\Server DWORD value:

snapinfo_snaps_count (number of SnapInfo snapshots to be retained)

For clustered Hyper-V hosts (to be configured on each node in the cluster):

key: HKLM\Cluster\SOFTWARE\NetApp\SnapManager for Hyper-V\Server DWORD value:

snapinfo_snaps_count (number of SnapInfo snapshots to be retained)


The 255 limit is maximum number of snapshot you can have on a DataOntap volume.

The SnapInfo retention takes care of this situation of you not hitting this value.

Data ONTAP LUN means the LUN provisioned on NetApp DataONTAP storage.

You can use SnapDrive for Windows to create this LUN like you do for your VM's storage.




As for SnapVault integration:


Is there a solution for this in later releases of SMHV?

Is there a batch or powershell script available for this?






Newer versions of SMHV support SnapVault with clustered Data ONTAP natively and don't need a script or batch file anymore.


Is there something more specific you need that would require scripting?




 >>> Is there something more specific you need that would require scripting?

This is still 7-mode.  Just wanted to check if there was something available.

We don't have SnapMirror, only Snapvault so it would be good if the snapinfo directory would:

  • Be updated (in the same job) with the CSV related vaults.
  • Have the same snapvault retention as the CSV related vaults.

But I should be able to put something together.







Ok thanks for your fast answer.

So if i well understand, if i backup my 4 vm every day, i have to provisioning 4x50kb per day.

So as we can store atmost 255 snapshots, it means 200kb per day x 255 : 51 Mo.

Is it alright ?

So what is the type of lun for Snapinfo LUN ? Because when i choose HyperV type, Wizard of SMHV say :" make sure the snapinfo lun is on a data ontape lun."

Which is the type of lun to choose to make a data ontape LUN ?


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