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blackmesa
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VSS Application Quiescing

Hi guys,

I've been asked for my opinion and honestly, I don't have one due to my lack of experience with vSphere Replication; so I thought I would ask you for yours please.

I understand that application level quiescing requires either Windows 2008 Server or Windows 8 Server.  The 'Introduction to vSphere Replication' document states that VSS quiescing should work with applications such as SQL Server or Exchange.  But what are peoples thoughts and/or experiences with VSS quiescing for applications like SQL, Exchange and AD?  Has the replicated data been consistent when recovered at the DR site?  Do the database writers get flushed correctly/as expected?

Basically, does it work well and has anyone had any issues or problems with replicated transactional based data?  Is it suitable for purpose?

Also, I presume that if one were to have issues with say SQL on a recovered virtual machine, that this wouldn't be supported by Microsoft?  Since VMware Tools only invokes VSS I wouldn't see any reason why not?

Thanks for your time and hope to hear back with your thoughts/opinions!

Cheers... Smiley Happy

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vmroyale
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But what are peoples  thoughts and/or experiences with VSS quiescing for applications like  SQL, Exchange and AD?  Has the replicated data been consistent when  recovered at the DR site?  Do the database writers get flushed  correctly/as expected?

My experience has been that SQL 2005 SP2 and later on Windows 2003 and later is usually consistent. Usually is the key word though, in that is important to test the replicas for consistency. I can't speack to Exchange, as I have never replicated it this way. AD will depend entirely on the version of AD in use. vSphere 5.0 U2 and 5.1 support VM-Generation ID, which allows Windows 2012 DCs to be replicated this way and be supported. Check out http://blogs.vmware.com/apps/2013/01/windows-server-2012-vm-generation-id-support-in-vsphere.html for more info on this.

I'm not 100% certain on the SQL support from MS with this scenario either - I have heard conflicing reports and have not seen a definitive answer to this.

The approach I like to take with SQL (when possible) is to use replication, local .BAK files or agented backups and virutal machine backups that also get replicated to the DR site(s). This way you have multiple options to restore from, if one of them doesn't work for whatever reason. As mentioned earlier though, testing the replicas is crucial.

Brian Atkinson | vExpert | VMTN Moderator | Author of "VCP5-DCV VMware Certified Professional-Data Center Virtualization on vSphere 5.5 Study Guide: VCP-550" | @vmroyale | http://vmroyale.com

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vmroyale
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But what are peoples  thoughts and/or experiences with VSS quiescing for applications like  SQL, Exchange and AD?  Has the replicated data been consistent when  recovered at the DR site?  Do the database writers get flushed  correctly/as expected?

My experience has been that SQL 2005 SP2 and later on Windows 2003 and later is usually consistent. Usually is the key word though, in that is important to test the replicas for consistency. I can't speack to Exchange, as I have never replicated it this way. AD will depend entirely on the version of AD in use. vSphere 5.0 U2 and 5.1 support VM-Generation ID, which allows Windows 2012 DCs to be replicated this way and be supported. Check out http://blogs.vmware.com/apps/2013/01/windows-server-2012-vm-generation-id-support-in-vsphere.html for more info on this.

I'm not 100% certain on the SQL support from MS with this scenario either - I have heard conflicing reports and have not seen a definitive answer to this.

The approach I like to take with SQL (when possible) is to use replication, local .BAK files or agented backups and virutal machine backups that also get replicated to the DR site(s). This way you have multiple options to restore from, if one of them doesn't work for whatever reason. As mentioned earlier though, testing the replicas is crucial.

Brian Atkinson | vExpert | VMTN Moderator | Author of "VCP5-DCV VMware Certified Professional-Data Center Virtualization on vSphere 5.5 Study Guide: VCP-550" | @vmroyale | http://vmroyale.com
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mvalkanov
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Hi,

vSphere Replication currently released builds do not support VM-Generation ID (needed by Windows 2012 DC VMs). A future maintenance update release might add this support.

Regards,

Martin

blackmesa
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Thanks guys for the replies and information!  It has helped a lot. :smileygrin:

Cheers...

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