Microsoft has invested millions of dollars into Azure and Office 365, and their competitors are following suit with bona fide public cloud offerings of their own. But public cloud solutions are not for everyone. Organizations of many stripes have legitimate reasons for not wanting their restricted data on systems beyond their total control.
For many of these entities, on-premises Exchange Server is a messaging must. Microsoft continues to update the software with the assurance that any improvements made to its cloud-based stack will eventually trickle down. Increasingly, these features are adding layers of complexity to the already daunting task of running an enterprise-grade messaging system. It's easy to get lost when going through hardware capacity planning, setting up DAGs (database availability groups) and site resiliency, configuring mail routing, and making sure your users can actually connect to the system.
With that in mind, here are a few details you absolutely must get right before opening the doors to your new messaging environment.
Before you even download Exchange Server, you should have a good idea of how many users your system will need to support, any service-level agreements you may have in place, and how long a disaster recovery window your organization will require. These are very deep topics that are far beyond the scope of this article, but Microsoft provides some tools to help you plan this out.
First up is the Exchange 2013 Sizing and Configuration Recommendations article on TechNet. It will take you through the basics such as Active Directory CPU core to mailbox server CPU core ratios, networking configuration, required Windows Server hotfixes, and pagefile configuration. If you are familiar with Exchange Server 2010, you'll notice a few changes highlighted in this article for configuring Exchange 2013, such as no longer recommending a separate network for replication.
Once you've familiarized yourself with the core recommendations, it's time to dive into capacity planning. The Exchange Team Blog is a great source of information for this, and the group has published a comprehensive look at how to correctly size your environment. Don’t be discouraged by the mathematical formulae -- a sizing calculator is available for download to help ease you through the process.
A few TL;DR tips:
- Don't mess with RAID setups for your database volumes. That’s old school and no longer necessary due to performance improvements in Exchange. JBOD is fine, especial when using DAGs for high availability.
- Use one Active Directory CPU core for every eight mailbox CPU cores.
- Don't use hyperthreading on physical mailbox servers.
- Set up performance monitors for critical metrics such as AD query duration, IOPS on your database disks, and verifying the entire AD database can fit in RAM.
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