Microsoft® Exchange Server 2003 Scalability with SP1 and SP2

5.5 Storage Optimization for Exchange 2003 383

Chapter 5

The most complex environments where I have seen the best Windows

Active Directory service provided have been where the Windows Active

Directory architecture, administration, and operations staff was either the

same or sitting closely to the Microsoft Exchange infrastructure team.

However, in some scenarios, such as the burning topic of IT outsourcing,

an company might want to outsource its Microsoft Exchange environment

while keeping the ownership of the Windows Active Directory environ-

ment. This is by far the most complex case to deal with, and, as an out-

sourcer (or a customer), you should seriously envisage the utilization of a

dedicated resource forest for Microsoft Exchange, ensuring that the

Exchange infrastructure has ample control over the Windows Active Direc-

tory deployment and minimizing the dependencies. This is not the simplest

system to design and implement, but it has been done before, it works, and

it can deliver the value you can expect for most kinds of Microsoft

Exchange deployments: rock-solid and never-failing Windows Active

Directory service for Exchange components!

5.5 Storage Optimization for Exchange 2003

Optimizing the storage in Exchange 2003 will yield noticeable benefits quite

rapidly. Storage tuning has always been one of my favorite part-time fun

activities because it deals with very simple elements that haven’t greatly

evolved during the past few years. Given the improvements in CPU process-

ing and the cheap cost of such components as network adapters and mem-

ory, storage, an ever-growing asset to any company, is not the most obvious

matter to address if you intend to provide the highest levels of performance

at the most reasonable price, let alone the utmost availability and protection.

With Microsoft Exchange 4.0, disks were 2.1 GB in size, and the maxi-

mum number of production users you could host on a particular server was

severely limited by the size of the Information Store—16 GB; approxi-

mately 300 to 500 was the upper limit on the number of users you would

host on a single Microsoft Exchange server, with mailboxes hardly reaching

out beyond 20 MB. With Exchange 5.0 and subsequent releases, the store

database could grow virtually unlimited, and so could your maintenance

tasks and troubles if you were not careful enough. While hosting more that

300 users per server was in fact seldom observed, it contributed to the mul-

tiplication (proliferation by today’s standards?) of Exchange servers in

Microsoft Exchange Organizations.

384 5.5 Storage Optimization for Exchange 2003

Today, in 2006, disks are becoming denser. You can store several ter-

abytes of data within a cubic meter, but is it the quantity or the actual per-

formance that should be your concern?

When disk vendors announce a 470-GB disk drive, do you think that

this disk drive would perform as well as a 15,000-rpm 36-GB drive? The

answer is no because of the drive mechanics and magnetic encoding of data.

That has led me to recommend to my customers that they use configura-

tions that favor the number of spindles over the actual storage capacity.

Customers have deployed 146-GB disk drives and have seen their

benchmarks and performance tests fail miserably because of the inability of

the system to cope with the high request rate, known as I/O per second

(IOPS), imposed by many concurrent users issuing a growing number of

transactions, with each of these transactions containing a growing amount

of information.

Ultimately, you should tune your storage subsystem such that you can

turn an I/O-bound application, like Exchange 2003, into a CPU-bound

application. In short, you remove storage bottlenecks and move them to

other components—generally, CPU or network. Tests performed in labs

have shown—in a configuration in which system, memory, and network

bottlenecks had been eliminated—that storage optimization was showing a

direct impact on the overall Exchange 2003 performance.

This is the most critical component to tune for Exchange 2003. Bearing

in mind that performance is only one part of the equation, this can lead to

many choices, many options, and, often, tradeoffs in terms of performance,

availability, and of course, cost.

In this section, we are going to look into the topics that matter, those

that will make a difference as you design your server, with a constant focus

on business requirements. Availability (i.e., the ability to recover large quan-

tities of data within the best time frame) is a common need. Granted, the

Microsoft VSS from the Windows Server 2003 storage framework greatly

helps in these recovery situations, although this is not necessarily the only

or best or most cost-effective approach.

5.5.1 Windows Partitions Design Guidelines

When providing storage resources for Exchange 2003, you ultimately need

to create Windows partitions, using Logical Disk Manager, DISKPART, or

any other volume management tool, such that the partition can be format-

ted using the NTFS file system and later on used by Microsoft Exchange.