Exchange Server 2010 and Your hardware

Before you deploy Exchange Server 2010, 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-mail messages, voice-mail messages, faxes, contacts, and calendar information.

Successful Exchange Server administration depends on three things:
• Knowledgeable 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 2010 to provide your high-performance messaging needs. This brings us to the issue of hardware. Exchange Server 2010 should run on a system with adequate memory, processing speed, and disk space. You also need an appropriate data-protection and system-protection plan at the hardware level. Key guidelines for choosing hardware for Exchange Server are as follows:

• Memory Exchange Server 2010 has been tested and developed for maximum memory configurations of 64 gigabytes (GB) for Mailbox servers and 16 GB for all other server roles except Unified Messaging. For Unified Messaging, the maximum is 8 GB. For multirole servers, the maximum is 64 GB. The minimum random access memory (RAM) is 2 GB. 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 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 of RAM plus 5 megabytes (MB) of 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 Exchange Server 2010 runs on the x64 family of processors from AMD and Intel, including AMD64 and Intel Extended Memory 64 Technology (Intel EM64T). Exchange Server 2010 provides solid benchmark performance with Intel Xeon 3.4 GHz and higher or AMD Opteron 3.1 GHz and higher. 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. Look also at the speed of the front-side bus. The faster the bus speed, the faster the CPU can access memory. Exchange Server 2010 runs only on 64-bit hardware. The primary advantages of 64-bit processors over 32-bit processors are related to memory limitations and data access. Because 64-bit processors can address more than 4 GB of memory at a time without physical address extension, 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 At the time of this writing, 64-bit versions do not support Intel Itanium.

• SMP Exchange Server 2010 supports symmetric multiprocessors, and you’ll see significant performance improvements if you use multiple CPUs. Microsoft tested and developed Exchange Server 2010 for use with dual-core and multicore CPUs as well. The minimum, recommended, and maximum number of CPUs—whether single core, dual core, or multicore—depends on a server’s Exchange roles. Still, if Exchange Server is supporting a small organization with a single domain, one CPU with multiple cores 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. When it comes to processor cores, I prefer two 4-core processors to a single 8-core processor given current price and performance tradeoffs. An alternative is to distribute the workload across different servers based on where you locate resources.

• 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. Rather than use one large drive, you should use several drives, which allow you to configure fault tolerance with RAID.

• Data protection You can add protection against unexpected drive failures by using RAID. For the boot and system disks, use RAID 1 on internal drives. However, because of the new high-availability features, you might not want to use RAID for Exchange data and logs. You also might not want to use expensive disk storage systems either. Instead, you might want to deploy multiple Exchange servers with each of your Exchange roles. If you decide to use RAID, remember that storage arrays typically already have an underlying RAID configuration and you might have to use a tool such as Storage Manager For SANs to help you distinguish between logical unit numbers (LUNs) and physical disks. 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; you can rebuild the RAID unit to restore full operations and can continue operations if one of the drives fails. RAID 5 (disk striping with parity) offers good protection against single drive failure, but it has poor write performance. For best performance and fault tolerance, RAID 10 (also referred to as RAID 0 + 1), which consists of disk mirroring and disk striping without parity, is also an option.

• Uninterruptible power supply Exchange Server 2010 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. Without proper shutdown, this data can be lost before it is written to disk. Note that most write-back caching controllers have batteries that help ensure that changes can be written to disk after the system comes back online.

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 2010.

Source of Information : Microsoft Press - Exchange Server 2010 Administrators Pocket Consultant