QLogic 10000 Series Optimizing MS Exchange User Manual

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Optimizing MS Exchange with the QLogic 10000 Series Adapter

FabricCache Technology Processes Exchange Transactions Up to Five Times Faster

FabricCache technology makes caching I/O data from Exchange entirely transparent to the host, which improves reliability and reduces complexity.

KEY FINDINGS

•The performance of Microsoft® Exchange Server® is driven by the IOPS capability of the underlying storage solution. The QLogic® FabricCache™ 10000 Series 8Gb Fibre Channel Adapter multiplies the capabilities

of existing storage technology by integrating Fibre Channel storage network connectivity, flash caching, and embedded processing. QLogic 10000 Series’ FabricCache technology makes caching I/O data from Exchange entirely transparent to the host, which improves reliability and reduces complexity.

MICROSOFT EXCHANGE EVOLUTION AND ARCHITECTURE

The beating heart of the Exchange Server is the Microsoft Extensible Storage Engine (ESE) API, also known as Joint Engine Technology (JET) Blue. ESE is an indexed sequential access method (ISAM) data storage technology that also makes up the core of Microsoft Active Directory®. ESE provides transacted data update and retrieval capabilities, as well as a crash recovery mechanism to maintain data consistency even in the event of a system crash. Transactions in ESE are highly concurrent, making ESE suitable for server applications such as Exchange.

The I/O Gap

ESE and Exchange have benefited greatly as processor and memory performance keep pace with the promises of Moore’s Law. Storage technology has unfortunately lagged well behind the trend. This gap leaves Exchange starved for IOPS, which is the most critical factor in transactional performance. Microsoft heralded several new design features to help cope with this IOPS shortfall. Among them is the advent of database availability

EXECUTIVE SUMMARY

Few applications describe “mission critical” like the enterprise e-mail engine. An estimated 918 million users start their day by checking e-mail messages, appointment calendars, and task lists. The alwayson, always-connected global worker is never too far from this vital link.

The increased demands on the Microsoft Exchange Server make it critical to optimize the server’s I/O performance in the SAN. The

QLogic 10000 Series 8Gb Fibre Channel Adapter meets that need for high performance. By integrating a unique I/O caching architecture with Fibre Channel connectivity, the 10000 Series Adapter significantly increases the performance of transactional I/O (IOPS) and I/O read latency for large Exchange data volumes. This combined approach of enterprise server I/O with server-based I/O caching using flash memory delivers dramatic and smoothly scalable application performance.

This document is intended for IT leadership, Exchange administrators, and all those accountable for the performance of the Exchange messaging infrastructure.

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Optimizing MS Exchange with the QLogic 10000 Series Adapter

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groups (DAGs) to disburse the I/O load, as well as key changes to the Exchange caching mechanism. The most notable change is a write caching feature that collects the pieces of data headed for storage and organizes them in sequential, contiguous blocks. Contiguous blocks require fewer IOPS to retrieve the data. Therefore, data read operations see an indirect boost from this front-end operation, as shown in Figure 1.

Figure1. Bridging the I/O Gap

Improving Transactional I/O with QLogic 10000 Series

Despite these new improvements, Exchange transactions are still essentially small-block, random I/O operations that produce heavy loads on the storage array. The QLogic 10000 Series Adapter is designed especially to accelerate this specific kind of workload. The 10000 Series Adapter works seamlessly with Exchange to accelerate the delivery of e-mail.

EXCHANGE STORAGE DESIGN

Storage design is one of the most important elements of a successful deployment of Microsoft Exchange Server. To achieve a storage design that is optimized for reliability, performance, and price, it is critical that you follow specific, recommended guidelines.

Performance First

Two sizing characteristics define the storage needs of Exchange: capacity and performance. Capacity is the raw storage needed to hold all of the messages, attachments, and meeting notes. Performance is the ability to move that data to and from storage. While both features are important, storage design for Exchange solutions should first consider performance because it is the most challenging quality to control. Performance is driven by the IOPS capability of the storage solution.

Exchange 2010 Mailbox IOPS Profile

A key ingredient to a successful deployment of Exchange is an accurate assessment of individual usage patterns. These patterns are described in a mailbox profile.

The two most significant factors that predict Exchange 2010 database IOPS are the amount of database cache provided per user and the quantity of messages each user sends and receives per day. Table 1, published

by Microsoft, is based on a standard worker who uses Outlook 2010 in Cached Exchange Mode. The information has been tested to be accurate within plus or minus 20 percent using database cache sizes between 3MB and 30MB per mailbox. The average message size for validation was 75KB, although message size is not a primary factor for IOPS.

Table 1 provides estimated values for IOPS per user that you can use to predict your baseline Exchange 2010 IOPS requirements and includes all database I/O (database, content indexing, and NTFS metadata). It does not include log volume I/O, which typically adds 10 percent to the workload.

	Messages		Per Mailbox with a		Per Mailbox with
	Sent and	Database			Multiple Database
			Single Database Copy
	Received	Cache per				Copies
	per	Mailbox	Estimated	Read/	Estimated		Read/
	Mailbox	(MB)		Write			Write
			IOPS		IOPS
	per Day			Ratio			Ratio
	50	3	0.06	1:1	0.05		3:2
	100	6	0.12	1:1	0.10		3:2
	150	9	0.18	1:1	0.15		3:2
	200	12	0.24	1:1	0.20		3:2
	250	15	0.30	1:1	0.25		3:2
	300	18	0.36	2:3	0.30		1:1
	350	21	0.42	2:3	0.35		1:1
	400	24	0.48	2:3	0.40		1:1
	450	27	0.54	2:3	0.45		1:1
	500	30	0.60	2:3	0.50		1:1

Table 1. Database Cache and Estimated IOPS Per Mailbox Based on Message Activity

After a baseline is established, other tools from Microsoft can further refine the expected IOPS load:

•The Microsoft Exchange Server Profile Analyzer collects statistical information about existing Exchange environments to provide data to define user profiles.

•The Exchange 2010 Mailbox Server Role Requirements Calculator helps to quantify the needs for new and planned environments.

STORAGE DESIGN AND POTENTIAL IOPS

Every component in the storage path has an impact on throughput. Ultimately, drive speed and type define the maximum IOPS potential. Faster drives support more IOPS, as depicted in Figure 2.

Figure 2. Drive Speed Affects E-Mail Performance

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