The white paper, Microsoft Exchange Server 2003 Performance on VMware® ESX Server 3, discusses the performance and scalability of Microsoft Exchange Server 2003 when it is deployed within virtual machines (VMs) hosted by VMware ESX Server 3.0.1 on a Dell™ PowerEdge™ 6850 server with a Dell-EMC CX500 FC storage area network (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 VM can support up to 1,300 heavy users. Our experiments also show that consolidating multiple instances of these uniprocessor Exchange VMs on a PowerEdge 6850 can cumulatively support up to 4,000 heavy users while still providing acceptable performance and scaling. The complete paper is available in PDF format. This wiki page provides the highlights and a place to discuss and ask questions about the paper through the comments section at the bottom of the page.

Test System Configuration

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 Microsoft Exchange in both the physical and virtual environments. 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 16 GB 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 VMs were configured with the same operating system and application as in the physical system.

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 Drivers (for operating system only) 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
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


Physical Versus Virtual Performance

To compare the performance of physical and virtual environments, we conducted UP and SMP LoadSim experiments, first on the physical system, and then in the VMware ESX Server 3.0.1 virtual environment. The software stacks, Microsoft Windows Server 2003 running Microsoft Exchange Server 2003, were configured identically on the physical and virtual systems. Doing so enabled an “apples-to-apples” comparison between the physical and virtual setups. The results of these experiments are shown in Figure 2.

Exchange Server 2003 on VMware ESX 3 - The Dell TechCenter
Figure 2. UP and SMP Physical and Virtual Throughput Comparisons


Scale Up and Scale Out Performance

In addition to comparing the virtual to physical performance, we also wanted to study the scale out performance (by increasing the number of VMs) and the scale up performance (by increasing the number of virtual CPUs configured for each VM). We conducted experiments using the following configurations:

Scale out (increasing the number of VMs):

    • One, two, and four uniprocessor VMs
    • One and two dual-processor VMs
Scale up (increasing the number of processors per VM):

    • Uniprocessor and dual-processor virtual machines.

The results of these scale up and scale out experiments are shown in Figure 3. Exchange Server 2003 on VMware ESX 3 - The Dell TechCenter

Additional details, including system component-level testing of processors, memory, and NIC performance, are included in the full white paper: Microsoft Exchange Server 2003 Performance on VMware® ESX Server 3.

Please use the comments area below for discussion and questions about this white paper.