Is it possible to identify why an incremental backup is suddenly large?

[richardb]

Hello,

I've setup and running Veeam Agent for Windows for some months without any problems.

I backup two volumes C:\ & D:\. The Job runs daily and creates incremental backups of the size of ~2GB (more or less). Today, I noticed that the Backup runs longer than normal. After it finished, I saw that the amount for the C volume is as normal, but for D:\ however, 180GB were saved. I cannot comprehend, where this big delta comes from. To my knowledge, not more data than usually was changed.

Is there a way to inspect/debug the backup to get to know, what data (files/directorys) have changed in comparison to the backup a day earlier?

PS: I verified, that this was an incremental backup and not a full one.

Any help is appreciated.

Best regards

Richard

[HannesK]

Hello,
and welcome to the forums.

What backup mode are you using? With the default backup mode (entire computer), it's doing block-based backup.

So everything that causes blocks to change will create large incremental backups. My guess is that Windows defragmentation or something like that ran. What was the last thing that was changed on D:\ drive? I remember similar results (which are correct for block-based backup) after some Windows upgrades when Windows changed the disk layout.

Best regards,
Hannes

[richardb]

Thank you for your feedback Hannes.

I am using "File level backup", because there are two pretty large directories on D:\, that I've excluded from backup. From https://helpcenter.veeam.com/docs/agent ... tml?ver=50:

Compares the last modification time attribute of files on the Veeam Agent computer and files in the backup. This operation allows Veeam Agent to detect files that have changed since the previous job session.

That's why I was hoping, that there is some way for me to identify, which files exactly have been backuped since the previous job session.

What was the last thing that was changed on D:\ drive?

I checked the directories that have changed within the last day (according to Windows timestamps). But all those directories in summary are far away from the size of 180GB. I've also thought of Windows updates, but they should be on my C:\ volume.

[HannesK]

ah okay. did you check the entire volume and did exclusions based on https://www.veeam.com/kb3236? The question still is, whether file-based backup for block-based backup is configured.

there is no list / logfile because that would slow down backup operations.

with Windows upgrades I mean version upgrades. not the monthly security updates.

I still guess for defragmentation.

For a more precise answer, I recommend to open a support case that support can check the logs.

[richardb]

I use file-based backup. As the linked KB states, it's the only way to exclude files/folders?

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 there is no list / logfile because that would slow down backup operations.

Thanks, that's what I wanted to know.

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 I still guess for defragmentation.

I think you are right. I checked the Windows logs and defragmentation was run a day before for that volume. I just wonder, because defragmentation seems to happen automatically about once a month on my system and I've never noticed this having such an impact on the backup size. With the exception of the two excluded directories, there isn't much change on that volume.

It's not a big issue for me. I was just looking for a quick way to confirm which files have been backuped - which you answered above. I don't think a support ticket is necessary. Thanks for your reply and time.

[HannesK]

yes, the KB lists all options how to include / exclude. The easiest way is to select the whole volume and then exclude folders. That is example "Exclude files from backup using mask". by doing that, it's block-based backup. One can see that by the "volume level backup" next to the volume name (C:\ in the KB article)

yes, if defrag ran, then there is no need to open a case.