Exchange 2013 - Hyper-V not clearing Exchange logs after backup

Hi,

The other day our Exchange 2013 Server stopped incoming e-mails which I tracked down to there being less than 5GB disk space (out of 220GB).

After a quick search, it appears most of the space is being taken up by logs. For a quick solution I increased the VHD to 300GB but the logs seem to be growing at around 1GB per day.

Originally, our Hyper-V backup would clear the logs after every backup but it doesn't seem to be doing so now - We're using the built in Windows Server Backup.

Has anyone come across this before?

Thanks
Tom