Incremental backup taking too much time and size

[isusko]

Hello everyone,

I have a very basic set up where I have a Veeam Backup & Replication Server, which makes backup of some physical servers and virtual machines in a local network. But there is an issue that makes me be concerned nearly every week.

There is one particular backup job of a physical server that is configured like this:

Local Storage in a physical disk of the VB&R server.
Retention policy of 10 days, without keeping files for archival purposes.
Not doing synthetic full backups periodically.
Doing Active Full backups every Friday.
And lastly the backup schedule is every day of the week except Saturdays at 17:30 p.m.

Full backups average times and sizes are about 4/5 hours and 1.8TB. Incremental backups instead, takes about 15 minutes for 10 GB or less.

So what I'm expecting from this configuration is that all my backups last for 15 minutes except the longer ones on Fridays.

The problem here is that the incremental backup of Sundays for some reason takes too long (about 4-5 hours just like the active full backup) and it's very big size too (about 1.7 tb just like active full backup), causing a big collapse with my other backup configurations.

So my question is, what can be happening here? Our backed up server has nearly no activity on saturdays meaning there are no big data changes. Also how could I avoid this from happening? If I remove Sundays from my schedule, will it take too long in Monday's backup job as it's happening now with Sundays?

Thank you in advance,

Isusko

[wishr]

Hi Isusko,

Given you do not have Synthetic and Active full backups, and compact operations scheduled for Sundays, there is no reasonable explanation for this behavior, so I would suggest investigating it with our support engineers.

Thanks

[isusko]

Hello again Fedor,

I might have not been clear in my statement but I DO have Active full backups programmed for every friday, despite not having Synthetic backups.

And sorry for my reduced knowledge but what you mean by "compact operation"? I do have scheduled job on Sundays, but what I want is that job to be another incremental backup same as Mondays, Tuesdays, Thursdays and Wednesdays. So the Sunday backup will last for about 15 minutes just like the other incremental backups.

Anyways, how could I contact the support engineers?

Thanks for your reply.

[wishr]

Isusko,

If you scheduled the job to run on Sunday and do not specify active/synthetic full to be created on this day, it will create an incremental backup.

You can find the steps to create a case here.

The defragment and compact operation is described here. I'm suggesting checking these settings as well, just in case.

Also, are you sure your active full backup is finishing on Fridays and does not keep running until Sundays? You can check that in the history view.

Thanks

[isusko]

Sorry Fedor,

If you scheduled the job to run on Sunday and do not specify active/synthetic full to be created on this day, it will create an incremental backup.

I know, and this is what's actually happening, an incremental backup. The point that I don't understand is why this incremental backup is nearly equal in size and duration to the full backup as I mentioned before. You can check the sizes in the following image:

The defragment and compact operation is described here. I'm suggesting checking these settings as well, just in case.

All the options here are disabled:

Also, are you sure your active full backup is finishing on Fridays and does not keep running until Sundays? You can check that in the history view.

Yes I am pretty sure about this. Please ignore the error on the Sundays backup. As you can see in the image, the incremental backup is too heavy, and as you can also see in the previous images, the rest of the incremental backups are so light compared to these ones created on Sundays.

(Friday, 10th december. Sunday 12th of december)


Thanks again,

Isusko

[wishr]

Thanks for the details.

Based on the information provided, I suspect that for some reason a lot of blocks on the machine disks are changing between Saturday and Sunday and that causes the increase in the backup size. Our technical support engineers should be able to confirm that for you.

Thanks

[cb831]

Was there a conclusion for this issue.
My guess would be windows deduplication task running once a week on Sunday.

[Dima P.]

Hello Claus,

Indeed deduplication might affect the performance of the backup job. Thank you for updating this thread with the results!

[Plavi269]

Hi all,

I have the same problem with size, but additional the size is pretty much always the same. And this happens not only to me, but to a bunch of people in our company... while the others get a normal incremental size, and I can't find a logic in this. Here's what I'm talking about...



They all have file level backup, the same directories and 5 days retention policy...

So what's causing this odd behavior? And what is in this, always the same, incremental backup?

[Mildur]

Hi Plavi

With File Level Backups, bigger incremental are expected.
When you change a file with file level backup, the entire file must be backed up.
Example: If the user changes everyday the same 500MB Word File, 500MB needs to be backed up each day.

When you change a file with volume level backup, only a small part (changed blocks) of the file must be backed up.
Example: User changed a single picture with the size of 1MB in this 500MB Word File, 1MB needs to be backed this day.

Does your user are changing the same big files each day? How big are they?

Thanks
Fabian

[Plavi269]

Hi Mildur,

The user doesn't change or add anything that big... and every day.



Let's talk about my case. The incremental is always the same - around 7GB. I don't add anything new, specially that big and most definitely not every day.
My suspicion goes to outlook archive .pst file, but the thing is it's size doesn't change, but Windows always puts a today's date on it, so maybe Veeam thinks it should backup it. But, then again pst size is 10GB, so math doesn't add up...

https://ibb.co/g6vcChW

[Mildur]

Hi Mildur,

My suspicion goes to outlook archive .pst file, but the thing is it's size doesn't change, but Windows always puts a today's date on it, so maybe Veeam thinks it should backup it.

That would make sense. The PST file is changing constantly. As soon you open Outlook, the file will change.
If you do File Level Backup, the entire 10GB PST File must be backed up. That's the disadvantages of file level backup.

But, then again pst size is 10GB, so math doesn't add up...

You see 7GB, because Veeam Backups are compressed.

Thanks
Fabian

[Plavi269]

Aha, now we're getting somewhere...

I am, with my 7GB, small comparing to others who have 20+ GB incremental every day. So, if we can't change that behavior, maybe solution is to decrease retention policy from 5 days (daily backup) to 3 or maybe even 2 days... would that be ok? If user something deletes 2-3 days should be enough for restore? I mean, theoretically 1 day should do it, but then again... Is there some best practice for retention policy about minimum days?

[Mildur]

would that be ok? If user something deletes 2-3 days should be enough for restore? I mean, theoretically 1 day should do it, but then again... Is there some best practice for retention policy about minimum days?

Depends on your business requirements. But imagine a hacker has access to the computer, encrypt some files. You find out about that 1 week later but your backups of the healthy files are already deleted by retention