Synchronous backup of 2 VMs for a distributed application

[blanchet]

Is is possible to backup synchronously two VMs that host a distributed application without shutting down the VM ?

More details:

My company will deploy very soon Solidworks PDM Pro. According to the software vendor, this software requires two VMs to run
( the two VMs will run on the same ESXi node.)

- one for the SQL Server Database
- another for the file data archive


If I backup sequentially the VM, the backup will not be coherent, except if I shutdown the VM before.
I would like to know if Veeam has a solution for this business-case.

[HannesK]

Hello,
I never heard a way how to enforce VMware to create two snapshots of two VMs exactly (meaning same nanosecond or whatever is required) at the same time.

Independent from Veeam or any other backup software, the only way to do that is on storage level (two machines on same volume) or creating somehow consistency. One way would be to shut down the VMs (as you mentioned), or you could also shut down the application that nobody can change anything.

The question is, whether it's really needed. If you back up the SQL first, then there could be too much data on the data archive machine (SQL snapshot a few seconds older than archive VM). When I look at their blog post, then it seems to be not required to be exactly in sync. For their option 1, they do it separately.

Best regards,
Hannes

[blanchet]

Hi,

Thank you very much for the answer. It confirms that there is no easiest solution yet to backup a distributed application with Veeam.

Therefore, I will study with the vendor if I can have a single VM installation for PDM Professional, it will make easier backup.

Regards

[soncscy]

Sebastien,

Do you have a document that suggests you must have all components backed up at exactly the same time? Your post made me curious and I found the same document Hannes did, and I don't see that as a requirement; it looks like it handles it alright? Can you provide the backup requirements you found that state all components need to be backed up at exactly the same time or backed up "cold" (e.g., powered off)

[HannesK]

Hello,

a distributed application with Veeam.

just to be complete: it's the same with any other backup software.

To me it looks like an easy task to do it the way Solidworks suggests with two steps. Single VM is also mentioned by Solidworks, yes.

Best regards,
Hannes

[blanchet]

Do you have a document that suggests you must have all components backed up at exactly the same time? Your post made me curious and I found the same document Hannes did, and I don't see that as a requirement; it looks like it handles it alright? Can you provide the backup requirements you found that state all components need to be backed up at exactly the same time or backed up "cold" (e.g., powered off)

The Solidworks PDM Installation Guide 2021 says at chapter 10 https://files.solidworks.com/Supportfil ... 0Guide.pdf

A complete file vault backup must include backing up the file vault database and all physical file vault archive files. The database backup must be performed at the same time as the archive file backup to avoid any data loss from mismatched backup sets. Without both the database and archives it is not possible to recover the vault in case of failure.

Then the official procedure recommends to schedule a task inside each VM to backup all the required components. So it relies on NTP to backup all components at the same time. The restoration procedure is quite boring because there are many manual steps, that prevents automatic testing of backup. In this case, it is easier to power off all the VMs before the backup, so that you can directly restore the full VMs.

Because of all these drawbacks, I really prefer to have a single VM for Solidworks PDM Pro, so that I can leverage Veeam Backup to easily backup all the components at the same time. With Veeam Backup the restoration is super easy, I can also use SureBackup to automatically test my backups.

[Regnor]

I don't know Solidworks, but other software products which have similar requirements, like archiving solutions. If database and files aren't in sync then inconsistencies could happen.
In such cases the consistency is reached via job scripts, which either enable a backup mode (places the software in read only) or stop the services.

[Seve CH]

My company will deploy very soon Solidworks PDM Pro. [...]

- one for the SQL Server Database
- another for the file data archive


If I backup sequentially the VM, the backup will not be coherent, except if I shutdown the VM before.

Hi.
We use Solidworks.

This is a case of a file repository with a DB containing the pointers and meta data.

What we do is backup the file server first and MS-SQL Server next (2nd job). If required, we will use the transaction logs to do a point-in-time DB restore to match the file server.

Best regards.

[stubbint]

What is your underlying storage. Would a storage snapshot achieve the required outcome?

[Gostev]

I was going to suggest the same thing.

[Regnor]

I don't think a storage snapshot will change anything. The VMs still need to be snapshoted, and those snapshots won't be in sync.

[Gostev]

Correct, but it allows you to have crash-consistent storage snapshot where VMs are perfectly in sync. This is really the only way to ensure all disks of all VMs are snapshot at the exact same moment. I don't know how much it really helps though, as one VM may still have some I/O sitting in system cache and another one may have just finished flushing, so effectively you may still have a few seconds difference?

[Regnor]

Ok that's true, but I wouldn't go that way. Rather have the application and database in an consistent state before creating any snapshots/backups; if there's no way, then temporarily stop the services.

[Gostev]

The problem here is not a consistent state of a database or a file archive per say, but rather them being out of sync with one another in the backup. And since you can't stop multiple services at the very same moment either, what you're proposing is not really a solution either. The only real solution is for application to implement a command to stop everything in the correct order and without data loss. The functionality these custom LOB apps usually never have because it was not a requirement, and often can't be expanded with it because whoever wrote them is already long gone

[Regnor]

With consistent I also meant having both database and files in-sync
Perhaps I'm seeing this too easy, as I don't know Solidworks, but if I stop the Application I would think that neither the files nor the database can be changed afterwards. Of course someone could have open files/connections...
At the end either the manufacturer or the partners who implemented it should have some guidelines for the backup process; at least I hope so

[blanchet]

What is your underlying storage. Would a storage snapshot achieve the required outcome?

A storage snapshot would be a good idea, unfortunately, my underlying storages are Dell EMC Isilon and TrueNAS, both of them are not supported yet by Veeam Storage Plug-ins.

We are a small company with a moderate amount of Solidworks data, so we will implement the single VM solution. It should work and it will be easier to manage.

[HannesK]

yep, if single-VM is possible, then I would also go for single-VM deployment. that makes it easy.