With Production Checkpoints, do I still need Guest Interaction?

[CDunk]

Hi All,

We've recently completed an upgrade of our environment to:

• Windows Server 2016 Hyper-V on Nutanix

• A mix of guests, mostly Windows Server 2012 R2. All VM Configuration Version 8 with the latest Hyper-V Integration Services KB4072650 installed.

• Veeam B&R 9.5u4 with a ReFS repository

The primary reason for upgrading from our previous Windows Server 2012 R2 Hyper-V was to take advantage of the native Resilient Change Tracking which is working great so far. "Incremental" backups that used to take days to scan an entire 5TB VM now complete in less than 30 minutes!

Since upgrading we're now also able to take advantage of Hyper-V Production Checkpoints. All the reading I've done both on these forums and the Veeam KB tells me that a Production Checkpoint will leverage the Hyper-V integration services to invoke VSS in the guest and quiesce applicaitons such as MS SQL and Exchange to a state where an application consistent snapshot can be taken.

With that in mind, do I still need to be using Veeam's own Applicaiton-Aware Guest Processing? Our DBAs take their own regular SQL file level level backups, so we've always used "copy only" MS SQL interaction so as not to disrupt the backup chain, Veeam isn't doing anything to process the transaction logs. Is that still needed, or is it enough to rely on the Hyper-V native VSS features introduced with Production Checkpoints?

For Domain Controllers I'd still prefer to keep the Veeam interaction, just to be sure there aren't any USN rollback issues when a restore is done.

Cheers!

Chris

[PTide]

Hi,

"Incremental" backups that used to take days to scan an entire 5TB VM now complete in less than 30 minutes!

Maybe it's too late to ask since you've already upgraded, but was it with AAIP enabled or not? Asking because I remember seeing a similar issue some time ago. The guy reported that disabling VSS increased speed a lot.

With that in mind, do I still need to be using Veeam's own Applicaiton-Aware Guest Processing?

If you are OK with missing the option to rollback to a particular date/transaction using VESQL, then it's fine to disable AAIP.

Thanks

[CDunk]

Maybe it's too late to ask since you've already upgraded, but was it with AAIP enabled or not?

For this particular server AAIP was not enabled. The problem was that with Windows Server 2012 R2 Hyper-V and Nutanix SMB storage we couldn't do change block tracking. Hyper-V didn't do it natively and the Veeam driver didn't work with the Nutanix storage. So every incremental backup of a large VM required the backup proxy to read the entire .vhdx file to figure out what needed to be copied into the backup. Now with 2016 Resilient Change Tracking we can back up only those changed blocks.

[CDunk]

If you are OK with missing the option to rollback to a particular date/transaction using VESQL, then it's fine to disable AAIP.

Thanks for taking the time to reply PTide.

I've done some of my own testing today and with AAIP enabled I see IO getting frozen and resumed in the Applicaiton Event Log, and the Hyper-V Volume Shadow Copy Requestor service start in the System Event Log.

Disabling AAIP and instead enabling Hyper-V guest quiescence (with "Take a crash consistent backup..." unticked) I see the same event sequence, so can confirm the OS it still aware a backup is being taken an quiesces the VSS-aware applications.

Is it still the case that when using Hyper-V guest quiescence the SQL backup is essentially taken as "copy only" and won't disrupt the log chain for the DBA Team's own SQL-level backups / log shipping?

[Mike Resseler]

That is indeed correct. Since the Hyper-V guest quiescence doesn't use the SQL VSS underneath, those logs are not touched

[mburavtsov]

The statement above seems to be incorrect.
"Hyper-V guest quiescence" triggers VSS subsystem of the guest OS. If SQL VSS writer is available (exists and its service is running) it will be triggered too. Furthermore, SQL log truncation happens independently from VSS backup of SQL DBs. In simple terms, if you create a shadow copy that triggers SQL VSS writer, there is no log truncation executed automatically after that. Logs are truncated only after LOG BACKUP.
When LOG backup job is not enabled in Veeam job https://helpcenter.veeam.com/docs/backu ... ss_sql.png (you do not need to backup SQL transaction logs to Veeam repo), but log truncation is enabled in Guest Processing settings https://helpcenter.veeam.com/docs/backu ... common.png, Veeam executes BACKUP LOG %dbname % to DISK = 'NUL' after a successful backup