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dcampregher
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SQL2016 slow during the aware backup/replication

Post by dcampregher » Jul 06, 2018 12:29 am

Hello!
The customer has in your HyperV 2016 cluster one VM Windows 2016 with a SQL2016 within It.

When we start the Replication or the backup jobs of this VM with the Application Aware, the answer time of the SQL go down and the tasks associated with the SQL increase in 1000%. If we disable the app aware processing, the SQL still works fine with no major chances in the performance.

So the question is If this behavior is normal or is there any thing to do to have less impact on the SQL during the Jobs.

Vitaliy S.
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Re: SQL2016 slow during the aware backup/replication

Post by Vitaliy S. » Jul 06, 2018 11:28 am

Hello,

Do you have any SQL Server related messages in the Windows Event log of that VM when the backup process starts? What options did you select in the AAP settings? Is it the only VM residing on the same storage that experiences this behavior?

Thank you!

dcampregher
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Re: SQL2016 slow during the aware backup/replication

Post by dcampregher » Jul 06, 2018 3:53 pm

Hino Vitaly!
This VM is alocated in a 3PAR ALL Flash with some other VM, but there isso a CSV dedicated for this VM.

The more weird is that only with the AAP the SQL go to a Very slow with crash consistent the SQL stay very Fine. The AAP is configured to do a copy only backup.

I didn't anything inside the VM. No log checksum and etc...

The Veeam support says that this os a normal behavior.

Vitaliy S.
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Re: SQL2016 slow during the aware backup/replication

Post by Vitaliy S. » Jul 09, 2018 1:35 pm

I would not say that it is absolutely normal behavior for a SQL Server to stun for some time. However, during application-aware process a VSS snapshot is created and all SQL Server related VSS writers and providers prepare the application for a consistent backup. As an idea, you can possibly try reproduce this manually and see if you experience the same behavior or not. If this SQL Server under heavy load, then it should be possible to observe the similar behavior.

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