Synthetic fulls

[perjonsson1960]

Folks,

When B&R has written a new synthetic full, and is finished writing the new full backup file, it seems that it starts to read all the files that have been used for the synthetic full; the previous full backup file plus all the incrementals following it. Why is it doing that? Is it some kind of "health check" that it does? My full backup files are around 23 TB, so this process takes several hours... Therefore it is no problem to have time to see what it is doing by looking in the Resource Monitor Disk Activity.

Kind regards,
PJ

[Mildur]

Hi PJ

Are you sure, that the job has finished creating the synthentic full? Sounds to me that the backup job is still synthesizing the new full backup from the last backup full and incremental files.

If it was the health check, you can see that in the job statistics. But the health Check should only use the latest restore point, which doesn't involve the inactive chain. Can you share a screenshot of the job statistics with us?
You can also go to job settings to see if health check was enabled for the day when the synthetic full is scheduled:
https://helpcenter.veeam.com/docs/backu ... ml?ver=110

Thanks
Fabian

[perjonsson1960]

The statistics doesn't say much, it just reflects the latest incremental backup that preceeded the start of the synthetic full creation. And the normal health check is scheduled on the third Saturday of the month.

I have been monitoring the disk activity in the Resource Monitor in the repository server, and it has only been reading the files since 14:10, and the time is now 16:46. And the new full backup file was last modified at 14:10, and is closed. I just want to know what it is doing, and the reason for it.

[Mildur]

The job session details should tell you exactly what's currently happening. Tasks for creating synthetic full or health check are both visible in the job's session details. At least for VM and "Managed by Server"-agent jobs.
https://helpcenter.veeam.com/docs/backu ... ml?ver=110
I cannot help without seeing a screenshot of the current job run.

One question, do you use reFS as the filesystem? Is the synthentic full done with FastClone?

Addionally, if you feel something is wrong, please open a case with our support team. They can check the debug logs and tell you exactly what happened in the job session.

Thanks
Fabian

[perjonsson1960]

Yes, we use ReFS, inline data deduplication, and Fastclone is used.
It is an Agent Backup of our Fileserver Cluster with two physical machines.
No, I don't think anything is wrong, I was only interested in knowing what it is doing after it has finished writing the new full backup file.