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Exchange Server on AWS
Quick Start Reference Deployment Guide

250 Mailboxes

Quick Start Architecture Deployment Scenario for 250 Mailboxes

For small or medium-sized deployments, you may want to consider a design that utilizes the minimal amount of infrastructure to provide high availability, meaning one Exchange 2013 multi-role server per Availability Zone. Figure 18 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 that supports 250 Exchange mailboxes.

250 Mailbox Deployment Scenario
Mailbox Size 20 GiB
Total Items Send/Receive per Mailbox Daily 200
Average Item Size 75 KiB
Exchange Instance Type r3.xlarge (4 vCPU, 30.5 GiB)
Required Memory per Exchange Server 24 GiB
Server CPU Utilization 37%
Number of DAGs 1
Total Number of Exchange Databases 10 (28 mailboxes per database; includes 10% projected growth)
Exchange Databases per Amazon EBS Volume 1
Amazon EBS Volumes per Exchange Server Instance 11 volumes (1 TiB each; includes restore volume)
Number of HA Database Copies per DAG 2
Number of Lagged Database Copies per DAG 0
Data Overhead Factor 20% (to account for unexpected database growth)
Backup Methodology Software VSS-based backup
Amazon EBS Volume Type General Purpose (SSD)
Exchange Server Instance Count per AZ 1
Exchange Server Instance Count Total 2

Figure 18: Sample Deployment Scenario for 250 Mailboxes

The R3 memory-optimized instance types are good candidates for running Microsoft Exchange Server 2013 on AWS, but you can choose any instance type that makes sense based on your requirements. The r3.xlarge, r3.2xlarge, and r3.8xlarge instance types support Amazon EBS optimization and high network performance, and the r3.8xlarge instance type supports 10 gigabit network connectivity. All of the memory-optimized R3 instance types support enhanced networking.

The r3.xlarge instance type provides 30.5 GiB of memory, which is well over the requirements estimated by the calculator, as shown in Figure 18.

Important

With only two highly available database copies, Exchange Native Data Protection is not recommended, and you should implement your own backup solution. This design uses a maximum mailbox database size of 750 GiB. You may need to consider a smaller database size limit that meets your Recovery Time Objective (RTO) requirements for database restores. In this design, each Exchange Server has been provisioned with an additional Amazon EBS volume dedicated to data restore procedures.

Microsoft recommends against multiple databases per volume when there are fewer than three highly available database copies in a DAG. Therefore, this design uses a one-database-per-volume model.

Note

This Quick Start will deploy two Exchange servers across two Availability Zones to support this design scenario. However, we only provision one additional Amazon EBS volume per server for Exchange databases, because the default Amazon EBS volume limits must be increased to support the number of volumes required in this design. This can be handled as a manual post-configuration task, after you've requested a limit increase.

Preferred Architecture Deployment Scenario for 250 Mailboxes

Designing an architecture aligned with the Exchange PA provides greater tolerance to failures and eliminates the requirement for traditional backups. The sample scenario for 250 users in an architecture based on the Exchange PA is shown in Figure 19, which 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.

250 Mailbox Deployment Scenario
Mailbox Size 20 GiB
Total Items Send/Receive per Mailbox Daily 200
Average Item Size 75 KiB
Exchange Instance Type r3.xlarge (4 vCPU, 30.5 GiB)
Required Memory per Exchange Server 16 GiB
Server CPU Utilization 23%
Number of DAGs 1
Total Number of Exchange Databases 40 (7 mailboxes per database; includes 10% projected growth)
Exchange Databases per Amazon EBS Volume 4
Amazon EBS Volumes per Exchange Server Instance 10 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 2
Exchange Server Instance Count Total 4

Figure 19: Sample Deployment Scenario for 250 Mailboxes Based on the Exchange PA

This design provides two Exchange servers per Availability Zone. Therefore, the memory and CPU requirements per server have been reduced compared to the previous one-server-per-zone design.