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Posts Tagged ‘IIS’

Function: Remove-IisLogFile – Purging Old IIS Log Files with PowerShell

November 21st, 2016 No comments

PowerShell-logo-128x84If you’re not careful, your server running IIS can create a LOT of logs. The default location for logs is in a sub-folder for the specific web site in c:\inetpub\logs\logfiles\. You can imagine the problems that will happen when your OS drive fills up with logs… things tend to not go so well, and the phone starts to ring. We can’t really just disable logging, as log files are an invaluable resource used in troubleshooting, planning, and maintenance.

Ryan over at Ryadel wrote a great article on adjusting the logging for IIS to be a little more helpful, and to minimize bloat. But we still need to watch for the accumulation of logs and the disk space they take. Ryan includes a two-line method of cleaning up the files in a single IIS site. But some servers, such as Lync and Skype for Business front end servers, have multiple web sites defined. I’ve taken Ryan’s method a bit further by incorporating an idea presented in a Stack Overflow thread, tweaked it a bit, and now we have some code that will clean up all log files that are older than 180 days for all websites on a server. Obviously, that time frame can be adjusted. Here it is the simple method:

Import-Module WebAdministration
$start = (Get-Date).AddDays(-180) 
foreach($WebSite in $(Get-WebSite)) {
  $logFile = "$($Website.logFile.directory)\w3svc$($website.id)".replace("%SystemDrive%",$env:SystemDrive)
  if (Test-Path $logfile){
    Get-ChildItem -Path "$logFile\*.log" | Where-Object {$PSItem.LastWriteTime -lt $start} | Remove-Item -Force
    # Write-Output "$($WebSite.name) [$logfile]"
  }
}

By adjusting the number at the end of the second line, we tailor the maximum age of the logs. In the above example, we’re keeping 180 days of them. We could put that code into a script and call it with a scheduled task to automate the cleanup, essentially creating a self-cleaning server. We can also wrap that code into a function and toss it into the PowerShell profile on the web server, allowing us to run it whenever we need to:

function Remove-IisLogFile{
    [CmdletBinding()]
    param(
        [Parameter(ValueFromPipeline, ValueFromPipelineByPropertyName)]
        [int] $age = 180
    )
    Import-Module WebAdministration
    $start = (Get-Date).AddDays(-$age) 
    foreach($WebSite in $(Get-WebSite)) {
      $logFile = "$($Website.logFile.directory)\w3svc$($website.id)".replace("%SystemDrive%",$env:SystemDrive)
      if (Test-Path $logfile){
        Get-ChildItem -Path "$logFile\*.log" | Where-Object {$PSItem.LastWriteTime -lt $start} | Remove-Item
        # Get-ChildItem -Path "$logFile\*.log" | Where-Object {$PSItem.LastWriteTime -lt $start}
        Write-host "$($WebSite.name) [$logfile]"
      }
    }
}

Then we can call it, optionally specifying the age of the log files we want to purge using the -age parameter. I incorporate the Test-Path code to ensure we’re not throwing an error for a website that is stopped and has never run. This is often the case in the aforementioned Lync/Skype for Business servers, where the default web site is disabled.

As you can see, PowerShell can be great at making sure your servers don’t get packed full of log files, while still maintaining enough logs to be helpful.

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