Archive-Logs.ps1

function Archive-Logs {
  [CmdLetBinding()]
  PARAM (
    [string][parameter(Mandatory = $true)][ValidateNotNullOrEmpty()]$LogsPath,
    [string][parameter(Mandatory = $true)][ValidateNotNullOrEmpty()]$ArchivesPath
  )
  BEGIN {
  }
  PROCESS {
    $today = (Get-Date)
    $date = Get-Date $today.AddMonths(-1) -day 1 -hour 0 -minute 0 -second 0
    $folders = Get-ChildItem -Path $LogsPath -Filter "W3SVC*"

    Write-Host "Archiving log files older than $date"

    foreach($folder in $folders) {
      New-Item -ErrorAction SilentlyContinue -ItemType directory -Path "$ArchivesPath\$folder" | Out-Null
      $files = Get-ChildItem -Path $folder.FullName -Filter "u_ex*.log" -ErrorAction Stop | Where { $_.LastWriteTime -lt $date }

      foreach($file in $files) {
        try {
          Write-Host ("{0}\{1}\{2}.zip" -f $ArchivesPath, $folder, $file.BaseName)
          Compress-Archive -Path $file.FullName -DestinationPath ("{0}\{1}\{2}.zip" -f $ArchivesPath, $folder, $file.BaseName)
          Remove-Item $file.FullName
        } catch [Exception] {
          $PSCmdlet.ThrowTerminatingError($_)
        }
      }
    }
  }
  END {}
}

Archive-Logs -LogsPath "C:\inetpub\logs\LogFiles" -ArchivesPath "C:\logs\iis"