What will happen if disk space is exhausted on a WSUS server?

Currently, I have a WSUS role installed on Windows Server 2012 R2. It downloads updates to a 500GB disk. The size of updates that it will download is more than the disk space, so what will happen after the space is exhausted?

The OS and WSUS updates on stored on different partitions.

Solution 1:

It happened to me in the past, just no new update will be downloaded, but it break nothing.

From newer WSUS's console you can disable patch storing on the WSUS server for the time you add space to your server.

Solution 2:

If the updates are stored on the same partition as the OS you're in for a night of fun. I would recommend storing the the updates on a different disk by changing the location where WSUS stores updates:

PATH\TO\wsusutil.exe movecontent <contentpath> <logfilepath> [-skipcopy]

If it's not the same partition as the OS it's still recommended to have sufficient space available. Best case scenario is that the WSUS service runs into an error, stops (or crashes) and can be started again once more space is available.