Gaining insight from consolidating and summarising Windows Event Logs.

Trawling event logs, man I’m excited. This is the kind of stuff I dream about and it’s what gets me going in the morning. I can’t wait to get stuck into millions of lines of events with the same error innocuous occurring every hundreds of times a second. With that one critical alert buried in all the noise.

I love it as much as I love grating my knuckles on a cheese grater.. Wait a minute, that sounds awful, hang on reviewing event logs is equally awful!

Now that I’ve wasted your time with my pointless preamble, here is how I’ve made things better. In my years reviewing event logs, I’ve taken a few learnings.

  1. It’s tedious
  2. It’s really tedious
  3. I want the information summarized
  4. I want to know if the error is new, or re-occuring.

Yes I can do all the above stuff manually, but why on earth would anyone want to! So I used powershell to improve things.

Let me set the scene. You’ve just patched a critical server and it’s been rebooted. Some of the first things you should review (yes really you should) is the windows system and application event log. So we RDP, open the event log, clikety clickety click and all is well. Sweet, move on to another 50 servers… Well that sucks. So here is a better way.

I produced the following script to do the following.

  1. Get all System and Application log events that are not Informational, so thats the Critical, Error, and Warning events
  2. Group them. If a certain event has repeated itself 1000 times, just tell me once and let me know how many times it appears
  3. Based on item 2, let me know the last time it appeared
  4. Was this event present before I rebooted the server (let’s look back 7 days as a line in the sand)
  5. Who on earth wants to log on to a server, let it take a ComputerName parameter instead
  6. Alternate credentials need to be specified as well as hey you’re running a best practice shop right 😉

Ok enough talk here is the script, hopefully it makes some sort of sense:

And the result?


A thing of beauty! A summarized at a glance view of the Windows event logs, to drive better insight and agile decision making in your environment. Strategic staircases, disruption, top down bottom up view, managerial speak etc.. etc.. Essentially, it good bro.

And there you go, lives saved! (from boredom that is, I’m not some kind of hero.. or am I??)

Hopefully that is of use to somebody, in a later blog I will talk about how you can display stuff like this in fancy HTML pages styled with bootstrap. I find that stuff so much cooler than grating your knuckles.