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Microsoft Exchange Server 2003 Performance on VMware® ESX Server 3
Virtualization has become a mainstream technology, allowing enterprises to consolidate underutilized servers
while helping to increase reliability and fault tolerance and simplify load balancing. As organizations embrace
virtualization in the data center, many may consider virtualizing Microsoft Exchange software. This paper
suggests how an enterprise-critical messaging application like Microsoft Exchange Server 2003 should be
sized and deployed on VMware® ESX Server1 to obtain a satisfactory Quality of Service. Specifically, we
examine:
?? The performance implications of running Exchange Server 2003 on a virtual machine versus a physical
system.
?? The performance of Exchange Server 2003 in virtual machine configurations when “scaling-up” (adding
more processors to a machine) and “scaling-out” (adding more machines).
Managed-Time ServicesManaged-Time Services On the MSP maturity scale, time-based managed services precede value-based managed ..... This paper discusses the performance and scalability of Exchange Server 2003 when it is deployed within
virtual machines hosted by VMware ESX Server 3.0.1 on a Dell® PowerEdge® 6850 server with a Dell-EMC
CX500 FC SAN. The Heavy user profile from Microsoft’s Exchange Server 2003 Load Simulator benchmarking
tool was used to simulate the Exchange workload. Results indicated that a uniprocessor virtual machine can
support up to 1,300 Heavy users. Our experiments also show that consolidating multiple instances of these
uniprocessor Exchange virtual machines on a PowerEdge 6850 can cumulatively support up to 4,000 Heavy
users while still providing acceptable performance and scaling.
A key observation in the study is that uniprocessor virtual machines are, from a performance perspective,
equivalent to half as many multiprocessor (two virtual processors) virtual machines. Hence we recommend
that the Windows and Exchange licensing costs, ease of management, and corporate standards guide your
configuration in this regard.
Microsoft Exchange Server 2003 Performance
on VMware ESX Server 3
1. When considering the deployment of Microsoft Exchange Server 2003 on a virtualization platform such as
VMware ESX Server, please refer to http://support.microsoft.com/kb/897615 for information about the Microsoft support
policy for their applications running in non-Microsoft virtualization software.
Microsoft Exchange Server 2003 Performance on VMware ESX Server 3
2 VMware, Inc.
Experiment Configuration and Methodology
The performance and sizing studies were done at the Dell Enterprise Solutions Engineering Labs in
collaboration with VMware engineers. The purpose of the tests was to measure, analyze, and understand the
performance of Exchange in both the physical and virtual environments. In the following sections the test bed
configuration used for the experiments is described in detail, and the test tools are discussed. Finally, we
present a description of the experiments.
Test Bed Configuration
In our test configuration the system under test (SUT) was a Dell PowerEdge 6850 server. The PowerEdge 6850
was configured with four 2.66 GHz dual-core Intel Xeon 7020 processors and 16GB of RAM.
In the physical environment, the system was running Microsoft Windows Server 2003 Enterprise Edition
(32-bit) and Microsoft Exchange Server 2003 with Service Pack 2 (SP2). In the virtualized environment, the
system was running VMware ESX Server 3.0.1, and the virtual machines were configured with the same
operating system and application as in the physical system.
The client systems were Dell PowerEdge 1855 blade servers, each with two 3.6 GHz Intel Xeon processors and
2GB of RAM. One client system was deployed for each Exchange mailbox store. The client systems were
running Microsoft Windows Server 2003 Enterprise Edition (32-bit) and Microsoft Exchange Server 2003 Load
Simulator (LoadSim). In addition to its function as a mail client, the first of these client systems also served as
the active directory server, the domain controller, and the DNS server.
Table 1 through Table 3 summarize the test setup in more detail.
Table 1. System Under Test (SUT) Configuration
Server Dell PowerEdge 6850
Processors Four 2.66 GHz dual-core Intel Xeon 7020 (eight total cores)
Memory 16GB DDR-2 400 ECC SDRAM
Hard drives (for operating system) Two 146GB 10,000 RPM drives in a RAID 1 array
HBA Two Emulex Fibre Channel HBAs
Virtualization software VMware ESX Server 3.0.1
Operating system (physical and virtual) Microsoft Windows Server 2003 Enterprise Edition (32-bit)
Application (physical and virtual) Microsoft Exchange Server 2003 with Service Pack 2
Table 2. Storage Configuration
Storage enclosure Dell EMC CX500 with one disk processor enclosure (DPE)
and three disk array enclosures (DAE)
Hard drives Fifty-four 73GB 15,000 RPM Drives
RAID configuration Eight 6-drive RAID 1+0 volumes for
Microsoft Exchange Information Store (IS)
One 6-drive RAID 1+0 volume partitioned into eight LUNs
for the transaction log
VMware, Inc. 3
Microsoft Exchange Server 2003 Performance on VMware ESX Server 3
Table 3. Client Configuration
Client Dell PowerEdge 1855 with four blade servers
Processors Two 3.6 GHz Intel Xeon per blade
Memory 2GB per blade
Operating system Microsoft Windows Server 2003 Enterprise Edition (32-bit)
Benchmark application Microsoft Exchange Server 2003 Load Simulator (LoadSim)
Microsoft Exchange Server 2003 Performance on VMware ESX Server 3
4 VMware, Inc.
Figure 1. Test Configuration Diagram
Client
(Dell® PowerEdge® 1855
blade servers)
Storage
(Dell/EMC CX500)
Fibre Channel switch
(Brocade Silkworm 3900)
Server
(Dell® PowerEdge® 6850)
Gigabit Ethernet switch
VMware, Inc. 5
Microsoft Exchange Server 2003 Performance on VMware ESX Server 3
Test and Measurement Tools
Microsoft LoadSim 2003, running on the client systems, was used to simulate messaging load for the physical
and virtual Exchange deployments. LoadSim provided the tools to measure how a system would respond
when supporting a given number of Exchange users, in this case Messaging Application Programming
Interface (MAPI) clients simulated using the LoadSim Heavy user profile. For a LoadSim run to be valid, 95%
of the response times experienced by these users must be less than 500ms. This ensures that the end users get
reasonable interactive performance.
The benchmark tries to closely model the normal daily email usage of real users in order to provide an estimate
of the number of users a system can support. While this benchmark is widely used to measure the performance
of Exchange platforms, as with all benchmarks the results may not match the specifics of your environment.
We used Windows Perfmon, a performance monitoring tool for Microsoft Windows operating systems, to
monitor performance on the physical Exchange setups. We configured Perfmon to log relevant CPU, memory,
disk, network, and system counters as well as Exchange-specific counters. These counters were logged to a
comma-separated value (CSV) performance log which was later imported to a spreadsheet for analysis.
We used esxtop, a performance monitoring tool for ESX Server, to record both ESX Server and virtual
machine related performance counters for the virtualized test cases. We configured esxtop to log processor,
memory, disk, network, and system counters during the LoadSim runs.
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