Script to compare file presence in directory structures

I'm still running into a few organizations that need to convert their sysvol replication from FRS to DFS-R. The process for doing that is quite straight forward, but if FRS replication is broken, then there is the risk that some data could be lost during this process.

As part of due diligence before converting, I like to compare the contents of sysvol among the domain controllers. The PDC emulator is the default source for new sysvol data. So, I compare that to other domain controllers. To help me with this I've created a PowerShell script that compares the files to identify any that are not the same on two servers.

I use this for sysvol, but you could use it to compare any two data structures. This script does not compare time stamps, file size, or file contents. It only looks for presence.

 

#Domain controller path to sysvol
$srcpath="\\Server1\sysvol"
$targetpath="\\Server2\sysvol"

#Get list of files
$srcfiles = get-childitem -Path $srcpath -File -Recurse
$targetfiles = get-childitem -Path $targetpath -File -Recurse

#Add property looks only at relative file name path
#Required for proper comparison without server name
Foreach ($file in $srcfiles) {

    $cleanpath = ($file.FullName).replace($srcpath,"")
    $file | Add-Member -NotePropertyName ShortPath -NotePropertyValue $cleanpath -Force

}

Foreach ($file in $targetfiles) {

    $cleanpath = ($file.FullName).replace($targetpath,"")
    $file | Add-Member -NotePropertyName ShortPath -NotePropertyValue $cleanpath -Force

}

$dif = Compare-Object $srcfiles $targetfiles -property ShortPath #-PassThru

Write-Host "Source ( <= ) is: " $srcpath
Write-Host "Target ( => ) is: " $targetpath
Write-Host ""
$dif

0x80070780: The file cannot be accessed by the system

Today got this error when trying to import a virtual machine on my newly rebuilt Hyper-V VM host running Windows Server 2019:

0x80070780: The file cannot be accessed by the system

I tried playing with permissions but it kept erroring out saying that it couldn't access the vhdx files. Finally, I realized that when I rebuilt the VM host, I forgot to install the data deduplication feature and thus the system could see the file names, but not access the deduplicated data.

After I enabled the data deduplication role service and rebooted, the system recognized the drives had deduplicated data and could access the files without issue.