Reddit, a popular online discussion site, has a running joke: people are often asked whether they would rather fight a horse-sized duck or 100 duck-sized horses. This question has surprising relevance to Office 365, because while Microsoft customers often worry about the threat of a widespread large outage (the horse-sized duck), they’re actually getting beat up by a larger number of smaller, less damaging but still annoying outages (the herd of duck-sized horses). There are a couple of deeper issues here that warrant a closer look to understand what the real risk is, and what you can do about it.
When designing for a migration to Exchange Server 2013, chances are you’ll have to deal with public folders. Given that Exchange 2013 has been around for a while, you might think such a task would be a proverbial walk in the park. Of course, if you are looking at a cookie-cutter environment, you might be right. However, in every design there are elements specific to the customer that require a different approach.
More specifically, consider the scenario in which you have public folders — possibly lots of them. For the sake of this article, let’s assume you have about 500GB worth in public folders spread over several thousand public folders across one or more replicas. For some customers, these numbers are much more than they have. For other customers, 500GB in public folders might just be a fraction of what they have to deal with. Regardless of your situation, public folders raise a rather interesting question: How do you plan for (a migration of) public folders to Exchange 2013?
Disk space is vital to the health of an Exchange Server. Without disk you don’t have email. 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 Mailscape, 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. Manually monitoring anything 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.