Exchange Server 2007 Architecture

Exchange server is constantly striving to meet the diverse needs of large and small companies, and is widely recognized by users. Today, however, business users of all sizes have new, similar needs for communication services-such as compliance, security, and disaster recovery. To meet these new challenges, the architecture of Exchange Server 2007 is updated to take advantage of the X64 bit hardware, simplify management and routing, and enable an Exchange server to assume one or more server roles.

Server role

Exchange Server provides a comprehensive information system that can run on a single server-meaning that all Exchange service roles are installed on one server, just as Microsoft Small Business server products. But having a flexible, modular system that can be installed on multiple devices can achieve significant benefits in deployment, management, and security. This concept was first introduced in Exchange Server, where front-end servers can be set up to transfer incoming Internet client protocols to the appropriate mailbox server. The front-end server is optional, which lowers the burden on the mailbox server and simplifies access to Microsoft Office Outlook Web Access (OWA) and Exchange ActiveSync (EAS) users. Setting up a front-end server in a medium or large organization enables Exchange to be more flexible by centralizing specific tasks on a limited number of servers.

In Exchange Server 2007, the Role-based Deployment feature has been extended to allow you to assign predefined roles to specific servers. These predefined roles enable organizations to control mail flow, improve security, and distribute services.

Customers typically customize the installation process for their Exchange Server 2003, creating specific server roles in a very manual way. In Exchange Server 2007, roles are predefined and can be selected during the installation process. The roles selected during installation ensure that only the required services and components are installed. This approach not only simplifies the deployment process, but over time, exchange management and hardware utilization is more efficient and straightforward, especially to enhance the maintenance of the scalability of the system, the Exchange Server role is as follows:
1. Client Access role. Similar to a front-end server in an earlier version of Exchange, which transfers access to Internet clients to the correct mailbox server.

2. Mailbox role. This role manages the user's mailbox, which is stored in a database that can be replicated or aggregated.

3. Central transmission role. This role provides internal routing of all information-including information from the Edge server, information from the Unified Messaging (UM) server, or information between two users on the same mailbox database. The central transport role is also where information strategies are implemented for information transmitted within and outside the organization.

4. Unified Messaging role. This role can be integrated with the switch to transfer voice mail and fax information to an Exchange mailbox and provide voice dial-in capabilities to Exchange server. This role and its services are described in more detail later in this article.

5. Edge Transport role. This server is outside your internal network, providing Exchange front-end message security, anti-virus and anti-spam services. Back-end filtering is provided by Exchange Hosted Filtering and is discussed later.

Because of the necessary communication with production network resources such as DNS and Active Directory, it is not recommended to place a typical Exchange server or any other domain member server in your Loop network (DMZ). But the Loop network is the ideal place to analyze incoming information and filter out unwanted or infected messages. Exchange Server 2007 introduces the Edge Transport role, which is not a traditional member of Active Directory or Exchange organization, but rather a spam or virus analysis of incoming information.

The Edge Transport role uses a service called EdgeSync that accepts traffic from the hub on the enterprise production network, so it is not necessary to open the TCP port from the edge to the production network. The Edge Transport role uses a lightweight version of Active Directory (ADAM) to hold its configuration information and other components, which are typically stored in Active Directory.

Information sent from the Hub Transport server to the Edge Transport server contains a list of recipients to verify that the recipient exists before the message is sent. Other information sent to the Edge Transport server includes the user's Safe Senders list. Microsoft Office Outlookreg; Or OWA users can add SMTP addresses to the Safe Senders List. The list establishes a path between the Hub Transport server and the Edge server, which allows information from users in the Safe Senders list to be sent to the Outlook user without being intercepted by the exchange anti-spam component.
Administrative groups and routing groups

In Exchange Server 2007, management is simplified and therefore more flexible. In previous versions of Exchange, administrative groups were administrative boundaries that contained servers and other objects. Administrative groups can be created to isolate management within an enterprise IT organization, but are not very flexible when created (you cannot move servers between administrative groups). Exchange Server 2007 Breaks this limit by removing administrative groups. Administrative permissions can now be delegated from the organization to the server. Whether your organization uses a centralized management model or a decentralized management model, you can delegate permissions to bring them closer to the model, and you can easily adapt to the new model as your organizational structure changes.

Routing groups have always been integrated with Active Directory sites. Because the design principles of Active Directory site boundaries are similar to the design principles of routing groups, they are the same in most organizations. Exchange now employs a routing topology based on the Active Directory site route. The Exchange routing topology and Active Directory site topology are no longer required to be maintained separately.

Storage group and Information store

Exchange Server 2007 Enterprise Edition supports up to 50 storage groups and 50 databases per server. You can set up to 5 databases per storage group and up to 50 databases. Compared with earlier versions of Exchange Server, mailbox data can now be distributed to more databases, and mailbox databases can be distributed to more storage groups. The Exchange Server Standard Edition supports up to 5 storage groups and 5 databases per server. There is no limit to the size of the enterprise and Standard editions of the database.

64-bit Advantage

Over the past few years, the Exchange server has developed rapidly in terms of the number of mailboxes and the average size of mailboxes. This includes a number of reasons-enhanced Exchange 5.5 sites, hardware is cheaper, WAN bandwidth is cheaper, increased information storage size limits, and users send more e-mail. For all of these reasons and even more, the organization has implemented smaller, larger servers instead of some of the less distributed servers. This strategy can achieve some cost and management benefits, but as more and more users are on fewer servers, performance becomes a problem at some point.

Enhanced performance and capacity can be achieved with 64-bit hardware and operating systems by giving exchange more resources. The 32-bit architecture allows only up to 4GB of addressable memory and is allocated between the kernel and the application. Upgrading the server and hardware architecture to 64-bit allows the operating system to address the maximum 16EB of memory. (The current hardware is limited to 16GB to 64GB RAM). A 64-bit processor can also get more cache capacity, meaning that the internal registers are twice times the size of a 32-bit processor register, which allows applications like exchange to write in a way that hosts more parts of the application on the processor- Dramatically improves performance and enables Exchange servers to grow along with growing information needs.

Another area where 64-bit performance has a significant impact is the number of input/output operations per second (IOPS). A 32-bit Exchange server with a large database can cause high IOPS if it is not set correctly for the disk subsystem. This means that you should design your storage subsystem by performance rather than by capacity-using some smaller disk drives rather than using fewer large disk drives and many of the disk space is not used.

Earlier tests showed that Exchange Server 2007, running on 64-bit hardware, required less than 75% of the ioPS of Exchange Server 2003 running on the same hardware. Another way to see this difference is that, to achieve the same performance, Exchange Server 2007 requires disk space that is One-fourth of Exchange Server 2003. This means that Exchange Server 2007 supports more and larger databases than earlier versions of Exchange. This also means that the disk subsystem is designed to consider capacity and performance.