Some Windows Server generates way too much dirty backups

[Robstarusa]

Another idea: Is there a swap/paging file in the guest that maybe is getting backed up ?

Another idea: If you have a network file server, perhaps connect the guest to that & make the guest disk size smaller & I think that may help with backups.

 

[wrhite]

My "maybe" solution for the "problem":

Open, and run Powershell as administrator:

1st: Optimize-Volume -DriveLetter C -Defrag -Verbose

Run this all avilable partition (C,D,E, F etc..)

Then shut off the VM, then power on.

Run PowerShell again:

2nd: Optimize-Volume -DriveLetter C -Defrag -Retrim -Verbose

Run this all avilable partition (C,D,E, F etc..)

3rd: Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\FileSystem" -Name DisableDeleteNotification -Value 1

(Check the value: Get-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\FileSystem" -Name DisableDeleteNotification)

Then Power Off, Power on again.

After theese, the first backup is a slow-full, but then my experiences after 2 days of backups:

The daily backup has been reduced from 6 hours to 1 hour, and there are still 2 servers to be do the defrag.

So it seems that the free space was very fragmented after the migration, so any small change generated a huge dirty bitmap in the free space as well.

Thanks

I've done this for one Windows 10 VM and it has certainly reduced the size of the backup.

In the attached log (vm1010 1040 1050.log) vmid 1010 has had your treatment, 1040 and 1050 have not.

Your suggestion has reduced the backup volume from >20% to around 10% but it is still ridiculous and not something I would want to run over a broadband connection. It is very mysterious because the windows VMs are doing nothing other than running our legacy windows app and MS Word. No web browser or other apps. All file storage is on the server so nothing really changes on the windows machine. All windows VMs are serving the same purpose with same configuration except 1010 is twice the size of the others.

Has anyone thought of other possibilities for the high volumes? Could it be that all the windows instances have dropbox and maybe google drive running?

Or is it to do with windows AV/security? or windows Store updates? or...?

Could it be the ballooning of memory amongst all my VMs?

For comparison, (see vm2001.log attached) our linux VM of 1Gb which is our mailserver and samba file server backs up around 2gb in between 30 and 90 seconds. This vm does have a lot of file activity being as I say our file and mailserver.

Suggestions welcomed!

[apologies for this edit] Could it be anything to do with all our VMs being on an ZFS raid? I don't know the magic description offhand but it is 3 x 4tB disks giving around 8tB usable space. Does the automatic ZFS shuffling behind the scenes cause things to happen that upsets teh dirty bitmap?

 

[SamTzu]

Stop picking on the good people at NSA. They are just trying to make our life simpler I mean safer.

 

[Jan Kratochvíl]

Hi, sorry for opening this old thread, but I'm still experiencing this problem. My W10 NTFS machines generate 10G backup every day doing nothing. I did all the stuff recomended above. Did anyone solve this? Is there some tool to monitor, what processes generate these writes?

 

[_gabriel]

Hi, sorry for opening this old thread, but I'm still experiencing this problem. My W10 NTFS machines generate 10G backup every day doing nothing. I did all the stuff recomended above. Did anyone solve this? Is there some tool to monitor, what processes generate these writes?

perhaps it's only the pagefile. you can try disable it temporarly in Windows VM then restart VM then compare future backups.

 

[Jan Kratochvíl]

pagefile.sys and hiberfil.sys it the first thing I disabled

 

[redmop]

Please be specific about what you did.

 

[Jan Kratochvíl]

Hi, my steps are:
- disable pagefile.sys and hiberfil.sys
- run Optimize-Volume -DriveLetter C -Defrag -Verbose
- run Set-ItemProperty -Path "HKLM:\System\CurrentControlSet\Control\FileSystem" -Name DisableDeleteNotification -Value 1
- run fsutil behavior set disablelastaccess 3

disable automatic defrag schedule