Hello,
I have 2 Mailbox Servers and 1 Client Access Server with DPM up and running for backups without any issues. I understand that if the DPM is running without any issues, it should purge the log files on the Exchange Servers. The total users in my organization is 110. For some reason, the C drive keeps filling up every month and I have increased it up to 120 GB now, it still runs out of space.