Exchange Server on AWS
Quick Start Reference Deployment Guide

2,500 Mailboxes

As you start to build designs that support thousands of users, the minimal infrastructure (two Exchange 2013 multi-role servers) becomes less practical. Generally this is due to the number of Amazon EBS volumes that you would need to attach to each instance. Designs built for a large number of mailboxes will typically require scaling out to multiple Exchange servers per Availability Zone, so you may want to consider following the Exchange PA for your architecture.

Figure 20 provides a summary of key inputs and outputs from the Server Role Requirements Calculator, along with suggestions for Amazon EC2 instance and Amazon EBS volume types to create a design supporting 2,500 mailboxes in an architecture based on the Exchange PA.

2,500 Mailbox Deployment Scenario
Mailbox Size 5 GiB
Total Items Send/Receive per Mailbox Daily 200
Average Item Size 75 KiB
Exchange Instance Type r3.2xlarge (8 vCPU, 61 GiB)
Required Memory per Exchange Server 48 GiB
Server CPU Utilization 57%
Number of DAGs 1
Total Number of Exchange Databases 56 (25 mailboxes per database; includes 10% projected growth)
Exchange Databases per Amazon EBS Volume 4
Amazon EBS Volumes per Exchange Server Instance 14 volumes (1 TiB each)
Number of HA Database Copies per DAG 3
Number of Lagged Database Copies per DAG 1 (7-day log replay delay)
Data Overhead Factor 20% (to account for unexpected database growth)
Backup Methodology Exchange Native Data Protection
Amazon EBS Volume Type General Purpose (SSD)
Exchange Server Instance Count per AZ 4
Exchange Server Instance Count Total 8

Figure 20: Sample Deployment Scenario for 2,500 Mailboxes Based on the Exchange PA

Now that we've increased the mailbox count to 2,500, the memory requirement per instance is 48 GiB. To accommodate this requirement, we've used the r3.2xlarge instance type, which includes 8 vCPUs and 61 GiB of memory.