Odd behavior backing up Windows 10 with Veeam Agent

[flomp]

Hi,

I am using Veeam Agent Free to back up my private Windows 10 Pro PC.

I noticed somewhat strange behaviour in the last few months:
Normally, my .VIBs are between 3 and 5 GiB, sometimes 8GiB.
Every month on the 3rd Wednesday (like today) my .VIB is unusually large. ~40 GiB
I did not do anything special on the day before and I do not know of any task which is scheduled to run at that date. (I also checked the Windows Task Scheduler)

I don't think that it's a bug in Veeam, I guess it's some program running on my pc - but I really don't know what...
Does anybody have an idea or has experienced the same?

My Backup settings:
- Daily at 1:30am
- Keep Backups for 35 days
- Create an active full each first Monday in the month
- no compression / no encryption

[ejenner]

I'm not sure if there are any differences between the free version and the paid version in terms of delta/master usage (I know it's configurable on the paid versions) but Veeam will move the master file around within the backup chain and delete old masters to best support your retention requirements. In some configurations the master will be the oldest file in the chain followed by deltas, in other configurations the master will be the newest file with deltas covering the previous incremental differences.

The other reason you'll see a large file is if the data being backed up has substantially changed since the last time it was backed up. Some processes can change the files on the disk so every file appears to be new, if this happens Veeam will see it as a new backup. If you are synchronizing your files with another location that might cause a problem like this. Even if you think all the files are the same files a synchrnoisation with a remote copy could make all the files appear new.

[Dima P.]

Hi folks,

Every month on the 3rd Wednesday (like today) my .VIB is unusually large. ~40 GiB
I did not do anything special on the day before and I do not know of any task which is scheduled to run at that date. (I also checked the Windows Task Scheduler)

Make sure that you do no have any Windows Update or disk defragmentation tasks scheduled for that time. Looks like you have some massive updates on the volumes, thus agent detects the changed blocks and store those within the incremental restore point.

I'm not sure if there are any differences between the free version and the paid version in terms of delta/master usage

There is no difference in the core engine - it works absolutely the same for all versions.

[flomp]

Thanks for your replies. I already looked everywhere I could imagine

I'm almost sure there is some application responsible for this, but I can't find out which one. However, it's not much of a problem... Also, there should be no defrag running as I have only SSDs.

When I find out sometime what caused this, I will provide an update

[Egor Yakovlev]

It is worth checking an antivirus software you have. Such big footprint change means some application massively accesses file system and it surely can be tracked down via disk monitoring tools(native Resource Monitor or Sysinternals Process Explorer in real time, or historical report via perfmon.exe->Data Collection Set). My antivirus shines like a Christmas Tree under "Disk Reads\s" during the scan.
/Cheers

[asdffdsa6131]

1. are you sure the 40GB file is a .vib and not a .vbk?
2. did you look at the advanced settings, such as "full backup maintenance"?
3. given that this happens on the same day every month, this is not from windows updates, defrag or from anti-virus software.
4. you are keeping only keeping backups for a short time period of just 35 days, so agent could be changing and merging the backup chain.

[flomp]

Ok, this is a bit embarassing

I disregarded the idea that it might be because of defragmentation very quickly as I was sure that Windows would not defragment SSD drives.

However, it turned out, that Windows actually does some "special" SSD defragmentation (and issues the TRIM command then, too). Also, it does that with a monthly period (even though weekly is set in the defragmentation settings).

See https://www.hanselman.com/blog/TheRealA ... urSSD.aspx
and https://answers.microsoft.com/en-us/win ... 5ede40d605

[asdffdsa6131]

i have been defragging floppy disks and hard drives for close to 40 years.

defrag might re-order the sectors in a continuous way.

but defrag does not change the size of files in a noticeable manner.
in fact, often a fragmented file is often smaller after defrag.

[zadrian]

I would think before changing anything....can you view files in your backup data set (or perform test recovery) ?
I could be a health-check or full bacckup (every 35 days as per setting ) ?

[Dima P.]

As a potential idea: try to record the history of disk I/O for the period of time when you see these changes, then you will be able to detect the process which is misbehaving. With the resource monitor you Collecting Data Over a Period of Time.