Backup log files into date-named archives with folder structure saving.

Backup-LogArchive.ps1

# Needed DotNetZip.dll from https://github.com/haf/DotNetZip.Semverd
# in script directory
param(
	$inputPath,
	$outputPath,
  $ArchivePrefix = 'Arch',
	$days = 7
)

$inputpath = $inputpath -replace '\\$' # remove trailing \
$outputPath = $outputPath -replace '\\$' # remove trailing \

$lastwrite = (Get-Date).Date.AddDays(-$days) # always use 00:00 as start time

# Load dll
$ionic = Join-Path $PSScriptRoot 'DotNetZip.dll' #Ionic.Zip.dll
if (-not (Test-Path $ionic)) {
	throw "Can''t find $ionic"
}
$dll = [System.Reflection.Assembly]::LoadFrom($ionic)
if (-not $dll) {
	throw "Can''t load $ionic"
}

$ArchiveName = '{0}\{1}{2:yyyy-MM-dd}.zip' -f $outputPath, $ArchivePrefix, $lastwrite

"Creating new $ArchiveName "
$zip = New-Object Ionic.Zip.ZipFile $ArchiveName
$zip.UseUnicodeAsNecessary = $true
$zip.UseZip64WhenSaving = [Ionic.Zip.Zip64Option]::AsNecessary # Always
Get-ChildItem $inputPath -Recurse |
Where-Object { $_.Attributes -notmatch 'Directory' -and $_.LastWriteTime -lt $lastwrite } |
Foreach-Object {
  $file = $_
  $dir = $file.DirectoryName.Substring($inputPath.Length)
  " Add $file to $dir"
  [void]$zip.AddFile($file.FullName, $dir)
}
"Saving $ArchiveName with $($zip.Count) files"
$zip.Save()
$zip.Dispose()