How to check size of Windows updates to be downloaded to Server Core

carbonbase used Ask the Experts™
I have a number of Windows 2012 Hyper-V hosts running Server Core.  These hosts haven't been patched since they were installed back in 2016.  I've just checked and these hosts only have 25GB of free space, is there a way of checking (even a rough estimate) what the size of the update download to these servers will be?  The updates will be deployed via WSUS and GPO.  Thanks.
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Most Valuable Expert 2013

Would be interested to know if there's a simple way to pull this too.

For individual updates you can get the display to show the file size but effectively you're looking at a "roll-up" of everything since 2016.
You could look at the store size on the WSUS server before and after downloading so you know roughly what is needed in capacity on each VM.

As a rule of thumb I assume you can get 50 updates per GB but that's a very rough average and doesn't account for Microsoft throwing in the odd Service Pack to spoil my math!
JohnBusiness Consultant (Owner)
Most Valuable Expert 2012
Expert of the Year 2018

I do not know either, but with all those updates to do, WinSXS will surely grow large and 20 to 30 GB is normal. So I would say your very tiny available space really limits you. Make your VM machine space larger.
Philip ElderTechnical Architect - HA/Compute/Storage

This article explains how to trim down the WinSXS folder to keep things under control.

Then, there's this one to clean things up yet further:
Dism.exe /online /Cleanup-Image /StartComponentCleanup

Open in new window

By running clean-up post updates the amount of free space on the server should remain relatively stable across its lifetime.
Hi All thanks for your comments.

So I haven't managed to find a definite answer to my original question but I've managed to make some progress.  As these are Hyper-V hosts on a fairly lightly used environment, I put one into maintenance and scanned and downloaded updates, there were 55 updates approved in WSUS which took up about 1.5GB after downloading.  So MASQ's rule of thumb proved quite accurate.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial