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7 Dell EMC SC Series: Microsoft Exchange Server Best Practices | CML1037
1.3 Exchange architecture
1.3.1 Exchange 2016
With CPU hardware generally less expensive than in the past, the constraint of expensive server hardware
has been alleviated. Exchange 2016 takes advantage of this with a primary design goal of simplicity in scale
and hardware utilization. The number of server roles has been reduced to two: Mailbox and Edge Transport
server roles.
The Exchange 2016 Mailbox server role includes all server components from Exchange 2013 Mailbox and
Client Access roles:
• Client Access services: provide authentication, limited re-direction, and proxy services offering the
usual client access protocols: HTTP, POP, IMAP, and SMTP.
• Mailbox services: including the back-end client access protocols, Transport service, Mailbox
databases, as well as Unified Messaging. The Mailbox server manages all active mailboxes on that
server.
Other enhanced features that are notable for storage considerations include the following:
In-place archiving, retention, and eDiscovery:
• Public folder support for In-Place eDiscovery and In-Place Hold
• Compliance Search: available only in Exchange Management Shell (EMS)
Improved performance and scalability:
• Search architecture redesigned as asynchronous
• Improved search scalability from 5K mailboxes to 10K mailboxes, or unlimited in EMS
To provide Exchange Native Data Protection, Exchange 2016 continues to use database availability groups
(DAGs) and mailbox database copies, along with features such as single item recovery, retention policies,
lagged database copies, and others. The high availability platform, the Exchange Information Store, and the
Extensible Storage Engine (ESE), have all been enhanced to provide greater availability, easier management,
and reduced costs.
With respect to storage, these enhancements include the following:
• Reduced IOPS compared to Exchange 2013: A reduction in IOPS/mailbox size enables larger
disks to be better utilized, providing capacity and IOPS as efficiently as possible.
• Multiple databases per volume: This enables multiple databases (mixtures of active and passive
copies) to be hosted on the same volume and is another enhancement that allows larger disks to be
used.
• Automatic Reseed for DAS disk failures: This provides a quick restore to database redundancy
after a DAS disk failure. If a physical disk fails, the database copy stored on that disk is copied from
the active database copy to a spare physical DAS disk on the same server. If multiple database
copies were stored on the failed disk, they can all be automatically reseeded on a spare disk. This
enables faster reseeds because the active databases are likely to be on multiple servers and the data
is copied in parallel.
• Automatic recovery from storage failures: This allows the system to recover from failures that
affect resiliency or redundancy. Exchange 2013 includes recovery behaviors for long I/O times,