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March 02, 2010

NetApp SMVI and App Consistent Backup / Recovery of SQL Server VMs

Posted by Abhinav Joshi – Reference Architect (Server and Desktop Virtualization)


I get this question asked very frequently that NetApp SnapManager for Virtual Infrastructure (SMVI) and integrated VMware snapshots (with the built-in VSS requestor) can be leveraged for application consistent backups of VMs hosting SQL Server databases. Considering this flexibility, why do we need the NetApp SnapManager for SQL Server (SMSQL) software inside the guest VM for application consistent backup/recovery?

That’s a great question. Let me start by highlighting that both solutions are valid and solve varied set of use cases. Every organization has tens to hundreds of SQL Server database VMs that can be classified as mission critical and non-mission critical databases. Both these types of databases have different RPO and RTO requirements. Application consistent backup of SQL Server databases is definitely the best practices recommendation from Microsoft. Both the SMVI and SMSQL solutions ensure application consistency and leverage space efficient storage array based NetApp snapshots; however the difference between the two solutions is primarily with respect to granular recovery, automated backup verification, and transaction log truncation. Let’s discuss this in greater details.

VMs with non mission critical databases: NetApp SMVI Solution


NetApp SMVI and integrated VMware snapshots solution is currently great for backups of the SQL Server database VMs that don’t require highest levels of RPO (less than 1 hour) and granular recovery (individual transactions and/or up to the minute restores) is not critical. This solution leverages the VMware VSS Requestor in VMware Tools to first create application consistent backups of the databases before invoking snapshot on the NetApp storage array.


However, the current implementation of VMware VSS Requestor in VMware tools provides the capability to create a VSS ‘copy’ only backups. The VSS copy backups provide the capability to backup databases and transaction logs but does not automatically truncate logs. This can result in disk full condition if the transaction logs are not truncated. Therefore scripts will have to be used to ensure transaction log truncation after backups, and provide capability for backup verification. One easy way to achieve automated transaction log truncation is to change the database recovery model to “Simple”. This ensures that the transaction logs get truncated at regular intervals, removing committed transactions. Also note that the current VSS Requestor implementation in VMware Tools does not support application consistency for Windows Server 2008 VMs. Therefore this solution is good for VMs with Windows Server 2003 as the operating system.


Therefore for such database VMs, SMVI only solution provides application consistent backup/ recovery for all the VM components (OS, application binaries, and databases). Here is the complete backup process workflow.


VMs with mission critical databases: NetApp SMVI + SMSQL Solution


NetApp SMSQL solution provides the capabilities to achieve VSS aware application consistent backups, automated backup verification, automated transaction log truncation, and automated granular recovery (both individual database transactions and up to the minute restores). Therefore this is an excellent solution for mission critical databases that demand highest levels of RPO and granular recovery. For such database VMs, the combined SMSQL and SMVI solution provides great value. SMSQL provides advanced levels of backup/recovery for individual databases and SMVI can be used for application consistent backup/recovery of the VM operating system and application binaries.


From an end to end solutions perspective, both these use cases are highlighted in greater detail in the joint Cisco, NetApp, VMware Solution Guide. For further details on SMVI and SMSQL, consider reading the NetApp SMVI Best Practices Guide (TR-3737)SnapManager for SQL Server Best Practices Guide (TR-3768).


Follow me on Twitter: @abhinav_josh


Jeff Wiggins

Does the method of attaching the storage impact either of the two methods? ie to use SMSQL do you need a FCP or iSCSI lun mapped to the guest OS?

Many newer installs are leveraging NFS for the vmware datastores so I'm wondering if it's possible for the data volumes as well.

Abhinav Joshi

Hi Jeff,
Thats a great question. As of today, SMSQL supports the following methods for hosting the database files:

3. iSCSI guest connected LUN using MS iSCSI s/w initiator

However, soon NFS datastores will be supported by SnapDrive/SMSQL for hosting data volumes. I cannot comment on the official release dates. Please feel free to email me at abhinavj@netapp.com if you need further information.



With the recent updates for ESX3.5 U5 and the latest vsphere updates, my understanding is that latest versions all support Windows 2008.

Therefore do you know if the VSS Requestor implementation in VMware Tools for the latest ESX\vSphere versions now supports Windows 2008?

I am particularly interested as I have non-critical Windows 2008 64bit OS vmguests running SQL2008 in various flavours.

So I am very keen for 2008 to be supported.


Abhinav Joshi


Thats a great question. I could not find any references to VSS requestor in VMware tools now supporting 'application consistency' for Windows 2008 VMs. I believe we will have to wait few more months. I am not allowed to say much more :)

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