Disk space is vital to the health of an Exchange Server. Without disk you don’t have email, thus Exchange monitoring - disk space is vital. Exchange is dependent on having disk because every time an email is sent it’s written to disk, without it you’re S.O.L.
When exchange databases run out of disk space the databases will dismount. Dismounted databases are usually not a good thing because that means email is down for the users in that database. Systems with low disk space can also impact overall performance of the server. Any of these events happening to an exchange server is not good. We all know that when email is slightest bit slow or down, the users will react like the zombies are attacking and the sky is falling.
Keep the zombies away…
If you are using tools such as ENow Exchange Monitoring, System Center Operations Manager, or Spotlight, monitoring Exchange disk space can be pretty easy. If your budget does not allow for third party software, however, you are left to monitor their servers manually. Manual Exchange monitoring can be a pain and not practicable for some shops due to the size of their environment. This is especially true if you’re running an environment with multiple Exchange 2010 DAG nodes, with replicating databases across many mount point paths.