White paper – QLogic 10000 Series Optimizing MS Exchange User Manual
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SN0430948-00 Rev.B 11/13
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Optimizing MS Exchange with the
QLogic 10000 Series Adapter
White Paper
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.
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.
After a baseline is established, other tools from Microsoft can further refine
the expected IOPS load:
•
tistical
information about existing Exchange environments to provide data to
define user profiles.
•
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.
Figure1. Bridging the I/O Gap
Messages
Sent and
Received
per
Mailbox
per Day
Database
Cache per
Mailbox
(MB)
Per Mailbox with a
Single Database Copy
Per Mailbox with
Multiple Database
Copies
Estimated
IOPS
Read/
Write
Ratio
Estimated
IOPS
Read/
Write
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
Figure 2. Drive Speed Affects E-Mail Performance