Is Application-Aware Processing risky?

[hasayeretFMG]

Good morning Veeamers,

Question for you all: up until now we've been doing our replications and backups without Application-Aware Processing option checked.
I was wondering if checking this option will:

1. Impact the source machine?
2. If the answer is "yes" to question number 1, is there a potential risk to the source machine?
3. Is Application-Aware Processing an absolute must-have when it comes to domain controllers and machines that are running SQL?

Thanks!!!

[nmdange]

If you have App-Aware processing disabled, but have the option "VMWare Tools Quiescence" or "Enable Hyper-V Guest Quiescence" set in the advanced storage settings, then there is no difference in the impact to the Virtual Machine. With AAP, Veeam connects to the VM to instruct it to do a VSS snapshot, with the other option, the Hypervisor uses the VM integration tools to instruct the VM to do a VSS snapshot. The end result is the same in both cases, you have an application consistent VSS snapshot.

If you have a SQL Server with databases in FULL recovery mode, Exchange without circular logging, or equivalent with Oracle, then App-Aware Processing is needed to truncate the logs. It would also be needed if you want to do continuous transaction log backups. It would not be needed if all the SQL databases are in SIMPLE recovery mode (or Exchange has circular logging enabled). For Active Directory, as long as your DCs are Windows Server 2012+ which is virtualization aware, then it is not needed at all. If your DCs are 2008 R2, well you need to upgrade them!

[hasayeretFMG]

Thank you!
Right now none of the options is checked. Our Exchange uses circular logs so I guess we don't need it, right?
As far as our domain controllers, we re using 2008r2 Datacenter - should I apply AAP on these?
In general, which one would you recommend using: The AA or the VMware Tools Quiescence?

Thanks!

[hasayeretFMG]

Also, is enabling one of these features risky to the source or not really?

[nmdange]

It is not safe to do a full VM restore of a Domain Controller running 2008 R2, see:
https://technet.microsoft.com/en-us/lib ... ontrollers

You can do individual object restore with either AAP or VMTools, using Veeam Explorer for AD. If you do a full VM restore of a 2008 R2 DC without following the proper procedure you will break your domain!

With Hyper-V, I would always recommend using Hyper-V Native Quiescence except with SQL transaction logs. I've read that there are sometimes issues with VMTools in VMWare, though I haven't run into that myself. You should always use either AAP or VMTools. If you are not using either one, then I would turn it on a few VMs at a time just to be on the safe side. The risk is small but not zero, as the VM's VSS will need to briefly pause activity to ensure a consistent backup. Of course I assume you run your backups during off-hours

[hasayeretFMG]

It is not safe to do a full VM restore of a Domain Controller running 2008 R2, see:

I am unable to open your link but I have done that in the past and I do not recall I had any issue...
Did anybody else here had issues restoring a 2008r2 DC?

[foggy]

If you have App-Aware processing disabled, but have the option "VMWare Tools Quiescence" or "Enable Hyper-V Guest Quiescence" set in the advanced storage settings, then there is no difference in the impact to the Virtual Machine. With AAP, Veeam connects to the VM to instruct it to do a VSS snapshot, with the other option, the Hypervisor uses the VM integration tools to instruct the VM to do a VSS snapshot. The end result is the same in both cases, you have an application consistent VSS snapshot.

This is not true, since AAIP is a bit more than just VSS quiescence. AAIP ensures that each VSS-aware application state is transactionally consistent by performing some additional application-specific steps to prepare the application for further VSS-aware restore. It is strongly recommended to enable AAIP on all Windows VMs, unless there are reasons to not do that.

As for the domain controllers, thanks to AAIP, possible issues upon restore (such as USN rollback) are handled automatically. I recommend reviewing this detailed KB describing all the nuances of domain controller recovery.

[hasayeretFMG]

As for the domain controllers, thanks to AAIP, possible issues upon restore (such as USN rollback) are handled automatically. I recommend reviewing this detailed KB describing all the nuances of domain controller recovery.

So what we're basically trying to do is to move the DCs between hosts and we wanted to do that via replication and planned failover. Will that do the trick?

[foggy]

Yes, and other users have already shared their positive experience regarding that with you in another thread.

[hasayeretFMG]

Thanks so much! will give it a shot!

[ITP-Stan]

What I like to do, for small companies without dedicated IT staff, is change the settings in the job to give a warning when application aware processing has a problem. Default is failing and having no backup.
For small companies it's more important to have a backup for which some applications might need some extra steps to recover, than to have no backup at all.
Off course it's important to then fix the underlying issue so that next time the AAP is working fine.