Determining Hardware and Software Components

Determining Hardware and Software Components

Justifying hardware and software purchases is often a difficult task for organizations of any size . It is therefore important to balance the need for performance and redundancy with the available funds available in the budget, and thus deploy the optimal Exchange server hardware and software configuration.

Server Number and Placement

Exchange scales very well to a large number of mailboxes on a single machine, depending on the hardware chosen for the Exchange server. Exchange Server 2003 also does not require dedicated systems for connectors, as did some previous versions. Subsequently, Exchange Server 2003 is optimal for organizations that want to limit the amount of servers that are deployed and supported in an environment.

Exchange 2000 previously had one major exception to this concept, however. If multiple sites required high-speed access to an Exchange server, multiple servers were necessary for deployment. Exchange Server 2003, on the other hand, introduces the concept of site consolidation, which enables smaller sites to use the Exchange servers in the larger sites through the more efficient bandwidth usage present in Outlook 2003 and the OWA and OMA technologies.

Server Redundancy and Optimization

The ability of the Exchange server to recover from hardware failures is more than just a " nice-to-have " feature. Many server models come with an array of redundancy features, such as multiple fans and power supplies , and mirrored disk capabilities. These features incur additional costs, however, so it is wise for smaller organizations to perform a cost-benefit analysis to determine what redundancy features are required. Midsize and larger organizations should seriously consider robust redundancy options, however, because the increased reliability and uptime is often well worth the up-front costs.

One of the most critical but overlooked performance strategies for Exchange is the concept of separating the Exchange logs and database onto separate physical drive sets. Because Exchange logs are very write-intensive, and the database is read- intensive , having these components on the same disk set would degrade performance. Separating these components onto different disk sets, however, is the best way to get the most out of Exchange.

In addition to separating the Exchange database onto a striped RAID5 set, the SMTP component used by Exchange can be optimized by moving it to the same partition as the database. By default, the SMTP component is installed on the system (OS) partition, but can be easily moved after an Exchange server has been set up. You can easily move the SMTP folder by accessing the Messages tab under the default SMTP Virtual Server in Exchange System Manager, as illustrated in Figure 5.7.

Figure 5.7. Moving the SMTP folder in ESM.

Server Memory and Processor Recommendations

Exchange Server is a resource-hungry application that, left to its own devices, will consume a good portion of any amount of processor or memory that is given to it. Although it operates best with multiple processors and more RAM, small organizations may not need the enhanced performance that this investment brings . The amount of processors and RAM required should reflect the budgetary needs of the organization. In general, 1GB of RAM and dual processors is a good rule of thumb for smaller organizations, but a single processor and as low as 500MB of RAM could also work.

Midsize and larger organizations should consider multiprocessor servers and greater amounts of RAM ”2GB or 4GB. This will help increase the amount of mailboxes that can be homed to any particular server.

NOTE

Any Exchange Server 2003 system with greater than 1GB of physical RAM should include the /3GB /USERVA=3030 switches in the boot.ini file, which optimize the memory allocation for these systems.

Server Operating System Considerations

Exchange Server 2003 is optimized for use with Windows Server 2003, and it is therefore logical to place Exchange on a server with the new OS installed. Exchange Server 2003 takes advantage of the increased security and feature set of Windows Server 2003, and is therefore the recommended approach for small organizations deploying Exchange.

NOTE

Although it is preferable to install Exchange Server 2003 on Windows Server 2003, this does not mean that the entire network needs to be Windows Server 2003 “only. All other servers, including Exchange 2000 and Windows 2000 Active Directory, can coexist in the environment at the same time.

The base OS for Exchange, Windows Server 2003, comes in two versions, Enterprise and Standard. Some midsize and larger organizations could deploy the Enterprise version of the Windows Server 2003 product, namely for clustering support. If this functionality is not required, the Standard version of the OS should be sufficient.

Small organizations, on the other hand, will almost exclusively require only the Standard version, rather than the Enterprise version, of the Windows Server 2003 product. The Enterprise version is required for concepts such as server clustering and support for more than four processors, which are seldom required for small server deployments.

Designing Clustering and Advanced Redundancy Options

In larger organizations, the need to ensure a very high level of reliability is paramount. These organizations often require a level of uptime for their email that equates to "5 nines" of uptime, or 99.999% uptime a year. For this level of redundancy, a higher level of Exchange redundancy is required than the standard models. For these organizations, support may be warranted.

NOTE

Clustering in Windows Server 2003 supports up to 8 nodes. It is now Microsoft's recommendation, however, that at least 1 node in a cluster be set up in passive mode for the most effective failover strategy. For more information on using clustering with Exchange Server 2003, see Chapter 30, "System-Level Fault Tolerance."

Small Organization Hardware and Software Design Decisions

Because 12 of the 15 employees were located in San Francisco, Company123 deployed a single Exchange Server 2003 system, running on the same hardware as the Active Directory and DNS components. It was designed to enable the three London users to access Exchange using the slow-link and offline capabilities of Outlook 2003.

Company123 decided to deploy server hardware with RAID redundant disks and dual power supplies and fans. Because messaging was a critical aspect for the company, the additional cost was determined to be warranted for the small organization. In addition, the Exchange database, SMTP engine, and Exchange logs were separated onto different physical drive sets, as illustrated in Figure 5.8. This helped Company123 to get the most out of its hardware investment.

Figure 5.8. Separating Exchange components on separate drive sets.

Company123 purchased enterprise-level server hardware with dual processors and 1GB of RAM. Because it was deploying all Active Directory and Exchange components on a single machine, it decided to invest in hardware so that its Exchange implementation would be relevant for several years to come.

The decision was made to deploy its Exchange Server using Windows Server 2003 Standard Edition, because the company wanted the optimal OS configuration for Exchange and didn't have any need for server clustering support.

Midsize Organization Hardware and Software Design Decisions

OrganizationY determined that Exchange mailbox servers would run in two sites, Manchester and Los Angeles, and that the St. Petersburg location and all other smaller sites would connect to these Exchange servers using the improved slow-link functionality in Outlook 2003. This significantly reduced hardware and support expenditures because the number of servers that would have been required was reduced to two for the entire organization, as illustrated in Figure 5.9.

Figure 5.9. Exchange organization with a reduction of servers.

Each server was optimized for the Exchange role with 4GB of RAM, quad processors, redundant fans and power supplies, and RAID controllers providing redundant disks. Each server had a separate RAID set for the OS, a separate one for the logs, and a RAID5 set for the database and SMTP folder, as illustrated in Figure 5.9.

The servers were installed with Windows Server 2003 Standard Edition. Because clustering was determined to be unnecessary, the Standard Edition of Windows sufficed.

Large Organization Hardware and Software Design Decisions

CompanyABC deployed Exchange mailbox servers in the largest sites : Minneapolis, San Francisco, Dallas, New York, Paris, Moscow, Tokyo, and Singapore. All other users within the organization were configured to use the mailbox servers in these locations for email access.

The largest site, Minneapolis, clustered its Exchange mailbox Servers into a 4-node cluster, with 3 active nodes and 1 passive node. The server hardware for these cluster nodes was composed of enterprise grade servers with redundant fans and power supplies, 4GB of RAM, quad processor, and RAID redundant disks. The disk arrays were configured with separate RAID sets for the OS, Logs, and Databases/SMTP Folder, as illustrated in Figure 5.10.

Figure 5.10. Separate drive sets for an Exchange 2003 configuration.

The servers in the other large sites were configured with the same hardware, but without clustering capabilities. Windows Server 2003 Standard Edition was installed on all servers with the exception of the clustered servers, which were installed with the Enterprise version of the software.