VMware Tools Quiescence and domain controllers

[rfn]

Hi,

Should VMware Tools Quiescence be disabled to backups and replications of domain controllers as well as for SQL servers?

Thanks!

[tsightler]

I would say VMware Tools Quiescence should be disabled for everything except maybe Windows 2000 servers which don't support VSS, and and even then, it's been known to caused corruption for AD or SQL controllers. I suppose another possibility is for Linux hosts, but I usually just snap those and accept that they will only be crash consistent. I never enable VMware Tools Quiescence for Windows systems that support VSS, which is all Windows systems from Windows 2003 and above.

[rfn]

OK... not the answer I expected! What about fileservers and other servers that aren't running a database of any kind? Isn't data more protected by using VMware Tools Quiescence?

[Vitaliy S.]

That's right. We strongly recommend enabling application-aware image processing (Veeam VSS) for all Windows machines rather than using VMware Tools Quiescence. Provided that you have both options enabled in the backup job, then Veeam VSS will be used.

What about fileservers and other servers that aren't running a database of any kind?

You may use VMware Tools Quiescence in this case, though data is more protected when Veeam VSS is enabled.

[tsightler]

OK... not the answer I expected! What about fileservers and other servers that aren't running a database of any kind? Isn't data more protected by using VMware Tools Quiescence?

No, the data is more protected with VSS, not VMware Tools Quiescence. The VMware Tools Quiescence driver is a horrible hack designed for systems which simply have no other options. VSS is an API provided by Microsoft to provide consistent imaging of the filesystem and applications during snapshot operations. You should use Veeam VSS provider, which leverages the Microsoft VSS infrastructure, in all cases if it is available.

I personally never use VMware Tools Quiescence because I've never seen it be of actual value but I've seen it cause actual problems with corruption.

[rfn]

OK... just to be sure... can VMware Tools Quiescence actually damage the source or is it only the backup that is in bad state? I do have Veeam VSS enabled for my backups so I guess that I'm pretty safe, but if VMware Tools Quiescence can damage the source then I can just as well disable it in the jobs completely. We only have Windows hosts.

Our mailserver, Kerio Connect, is based on single EML files for each mail and doesn't have a database. I'm pretty sure that it doesn't have a VSS writer, but does that matter? Should I just disable VMware Tools Quiescence anyway and have a crash consistent backup and never look at VMware Tools Quiescence again?

[joergr]

to be clear here: VMware tools quiescence actually CAN (under rare circumstances) damage your ad/exchange/sql database. I suggest not to use it. That is also the reason it is set to disabled by default in the new veeam b+r 5.

best regards,
Joerg

[rfn]

I will quickly disable it on our backup jobs... This is great knowledge, but maybe this should be explained better in the manual? When reading the manual it sounds like a feature that is definately good to have enabled...

I really appreciate all your replies. This forum is full of helpfull people!

[joergr]

Don´t hurry or worry, if you checked BOTH, the vmware tools quiescence AND veeam vss, b+r will ALWAYS use veem vss

[rfn]

Don´t hurry or worry, if you checked BOTH, the vmware tools quiescence AND veeam vss, b+r will ALWAYS use veem vss

I get that, but if VSS fails for some reason then I think that it will continure with quiescence and I would rather have the job fail.

[tsightler]

Our mailserver, Kerio Connect, is based on single EML files for each mail and doesn't have a database. I'm pretty sure that it doesn't have a VSS writer, but does that matter? Should I just disable VMware Tools Quiescence anyway and have a crash consistent backup and never look at VMware Tools Quiescence again?

Since your mail server uses EML files then it is basically using the filesystem itself as the database, thus the default VSS writer, which provides filesystem consistency during snapshot operations, should be perfect. You ALWAYS want to use VSS when available as, even without an application specific VSS writer, the default VSS behavior is to provide filesystem consistency.

[rfn]

OK... I didn't know that the filesystem itself used VSS. Does a regular snapshot in vCenter fascilitate VSS integration or does it just rely on quiescence?

[Gostev]

Regular snapshot through vSphere Client does not use either by default.

[Gostev]

to be clear here: VMware tools quiescence actually CAN (under rare circumstances) damage your ad/exchange/sql database. I suggest not to use it. That is also the reason it is set to disabled by default in the new veeam b+r 5.

I wonder if you may even know the guy who suggested to make this change in v5

[joergr]

Yeah yeah i think i know him quite well