Exchange Server 2007 and Your Hardware

Before you deploy Exchange Server 2007, you should carefully plan the messaging architecture. As part of your implementation planning, you need to look closely at preinstallation requirements and the hardware you will use. Exchange Server is no longer the simple messaging server that it once was. It is now a complex messaging platform with many components that work together to provide a comprehensive solution for routing, delivering, and accessing e-mails, voice mails, faxes, contacts, and calendar information.

Successful Exchange Server administration depends on three things:

• Good Exchange administrators

• Strong architecture

• Appropriate hardware

The first two ingredients are covered: you're the administrator, you're smart enough to buy this book to help you through the rough spots, and you've enlisted Exchange Server 2007 to provide your high-performance messaging needs. This brings us to the issue of hardware. Exchange Server 2007 should run on a system with adequate memory, processing speed, and disk space. You also need an appropriate data-and-system protection plan at the hardware level.

Key guidelines for choosing hardware for Exchange Server are as follows:

• Memory Exchange Server 2007 has been tested and developed for maximum memory configurations of 32 gigabytes (GB) for Mailbox servers and 8 GB for all other server roles. The minimum random access memory (RAM) allowed is 1 GB, with 2 GB of RAM as the recommended minimum. In most cases, you'll want to have at least twice the recommended minimum amount of memory. The primary reason for this is performance. Most of the single-server Exchange installations I run use 4 GB of RAM as a starting point, even in small installations. In multiple Exchange Server installations, the Mailbox server should have at least 2 GB RAM plus 10 (megabytes) MB RAM per mailbox. For all Exchange Server configurations, the paging file should be at least equal to the amount of RAM in the server plus 10 MB.

• CPU 64-bit versions run on the X64 family of processors from AMD and Intel, including AMD64 and Intel Extended Memory 64 Technology (Intel EM64T). Exchange Server 2007 provides solid benchmark performance with Intel Xeon 3.66 GHz, AMD Opteron 2.6 GHz, and AMD Athlon 2.6 GHz. Any of these CPUs provide good starting points for the average Exchange Server system. You can achieve significant performance improvements with a high level of processor cache. Look closely at the L1, L2, and L3 cache options available-a higher cache can yield much better performance overall.

  The primary advantages of 64-bit processors over 32-bit processors have to do with memory limitations and data access. Because 64-bit processors can exceed the 4 GB memory limit of 32-bit processors, they can store greater amounts of data in main memory, providing direct access to and faster processing of data. In addition, 64-bit processors can process data and execute instruction sets that are twice as large as 32-bit processors. Accessing 64 bits of data (versus 32 bits) offers a significant advantage when processing complex calculations that require a high level of precision.

  Note 

  Exchange Server 2007 32-bit versions run on Intel x86 or compatible hardware and are for testing, training, and evaluation only. 64-bit versions do not support Intel Itanium.

• SMP Exchange Server 2007 supports symmetric multiprocessors, and you'll see significant performance improvements if you use multiple CPUs. Microsoft tested and developed Exchange Server 2007 for a maximum CPU configuration of four dual-core CPUs with Mailbox servers and two dual-core CPUs with all other server roles. Still, if Exchange Server is supporting a small organization with a single domain, one CPU should be enough. If the server supports a medium or large organization or handles mail for multiple domains, you might want to consider adding processors. An alternative would be to distribute the workload to virtual servers on different systems.

• Disk drives The data storage capacity you need depends entirely on the number and size of the data that will pass through, be journaled on, or stored on the Exchange Server. You need enough disk space to store all data and logs, plus workspace, system files, and virtual memory. Input/output (I/O) throughput is just as important as drive capacity. In most cases, small computer system interface (SCSI) drives are faster than integrated device electronics/enhanced integrated drive electronics (IDE/EIDE) and are, therefore, recommended. Rather than use one large drive, you should use several smaller drives, which allows you to configure fault tolerance with redundant array of independent disks (RAID).

• Data protection Add protection against unexpected drive failures by using RAID. For data, use RAID 0 or RAID 5. For logs, use RAID 1. RAID 0 (disk striping without parity) offers good read/write performance, but any failed drive means that Exchange Server can't continue operation on an affected database until the drive is replaced and data is restored from backup. RAID 1 (disk mirroring) creates duplicate copies of data on separate drives, and you can rebuild the RAID unit to restore full operations. RAID 5 (disk striping with parity) offers good protection against single drive failure but has poor write performance. For best performance and fault tolerance, RAID 0 + 1 is recommended. This consists of disk mirroring and disk striping without parity.

• Uninterruptible power supply Exchange Server 2007 is designed to maintain database integrity at all times and can recover information using transaction logs. This doesn't protect the server hardware, however, from sudden power loss or power spikes, both of which can seriously damage hardware. To prevent this, connect your server to an uninterruptible power supply (UPS). A UPS gives you time to shut down the server or servers properly in the event of a power outage. Proper shutdown is especially important on servers using write-back caching controllers. These controllers temporarily store data in cache, and without proper shutdown, this data can be lost before it is written to disk.

If you follow these hardware guidelines and modify them for specific messaging roles, as discussed in the next section, you'll be well on your way to success with Exchange Server 2007.