Deduplication with Hyper-v Cluster

[#1]

Hi

I have a 4 node Hyper-v cluster with 1 clustered shared volume.

After running deduplication on the volume used for CSV I get around 75% space savings, however the hyper-v cluster does not get any space savings.

How can benefit from deduplication if Hyper-v is not able to see the space savings?

I am using ISCSI LUN's.

Regards Martin

[#2]

Depending on your volume and LUN configuration duplicate blocks are either released to the volume or aggregate. The actual file system reported to Windows 2008 R2 does not change how much free space there is.  Space effienency is gained because with deduplication you can now fit more volumes with more Hyper-V LUN's on the same aggregate.

-Robert

[#3]

OK that makes sense, however what is the best practise then for creating volumes and LUN's for Hyper-v?

Should I turn off space reservation so I can create more volumes and luns and add additional CSV's into my hyper-v cluster?

Please advise...

I have been looking for an update on the Microsoft Virtualization Best Practise whitepaper from NetApp but it seems it overdue by a month.

[#4 · Accepted solution]

Hi Mes.  Yes, best practice is to make 'skinny LUNs' and untick Space Reservation off the LUN.  As mentioned before, the Windows OS will not see the benefits but the parent volume will as the blocks will be visible/accessible at this level making it possible for your other LUNs in the same Vol to have access to these free blocks.  This is what we are doing in our set up.  The best practice doc should be arriving soon, TR3702 version 3.  They are almost done with it.  Hope this helps.  Ping me back if you have any other questions.

- Jeff

[#5]

Looks like your question has been answered, but I wanted to let you know that updated versions are available hot off the presses as of early this morning:

• NetApp Storage Best Practices for Microsoft Virtualization (TR-3702)
• NetApp Implementation Guide for Microsoft Virtualization (TR-3733)

Check out our NetApp for Microsoft Environments Blog for a recent post from the author and a new series on Netapp storage layout for Hyper-V.

It's been a great week for new content; we published two additional reports plus a new demo:

• Best Practices: SnapManager for Hyper-V (TR-3805)
• Exchange, SQL Server, and SharePoint Mixed Workload on Microsoft Hyper-V and NetApp Fabric MetroCluster (TR-3804)
• NetApp SnapManager for Hyper-V Demo (YouTube)

NetApp's new CSV-aware data protection tool automates backup, replication, recovery and even scripting to help maximize availability for your Microsoft virtual environment.

[#6]

jcampaz516 wrote:
Hi Mes.  Yes, best practice is to make 'skinny LUNs' and untick Space Reservation off the LUN.  As mentioned before, the Windows OS will not see the benefits but the parent volume will as the blocks will be visible/accessible at this level making it possible for your other LUNs in the same Vol to have access to these free blocks.  This is what we are doing in our set up.  The best practice doc should be arriving soon, TR3702 version 3.  They are almost done with it.  Hope this helps.  Ping me back if you have any other questions.
- Jeff

Jeff,

When you make skinny LUNS and untick space reservations, where are the free blocks go to? You say they will be available to the volume, but the tr doc says they will be available to the aggr.

Could you explain this? If they are going to the aggragate i would create another CSV for hyper-V in that aggregate. Otherwise i would create or expand the csv LUN in that volume.

Tomas