Virtualizing Exchange

Transcription

1 Virtualizing Exchange Simplifying and Optimizing Management of Microsoft Exchange Server Using Virtualization Technologies By Anil Desai Microsoft MVP September, 2008 An Alternative to Hosted Exchange Azaleos Corporation 1938 Fairview Avenue East, Suite 100, Seattle, WA USA tel /

2 Executive Summary Organizations encounter numerous challenges related to running Microsoft Exchange Server as a missioncritical backbone of their communications infrastructure. Virtualization technology can be used to solve most of these issues. IT managers can choose virtualization platforms from VMware and/or Microsoft to simplify deployment, reduce administration overhead, and to minimize overall costs. The Azaleos OneServer Virtual Edition offers a best practices approach to running Microsoft Exchange Server within a virtual environment. Exchange Server Management Challenges Organizations of all sizes rely on messaging as a critical component of their overall business operations. Accordingly, IT departments are tasked with providing high performance, high-availability, scalability, and disaster recovery for . New features in Microsoft Exchange Server 2007 make it an excellent choice for meeting users needs. However, IT departments must also address numerous potential management issues from complex topologies to unique deployment challenges. Managing a Complex Server Topology In order to meet the performance, scalability, and availability needs of a distributed messaging infrastructure, Microsoft has designed the Exchange Server platform to include numerous server roles. These roles include Client Access Server, Edge Transport Server, Hub Transport Server, Mailbox Server, and Unified Messaging Server. While this architecture provides for flexible deployments, it can also make deployment, configuration, and management more complex. The result is that systems administrators must spend more time in planning their deployments and managing multiple servers. Managing Hardware Resource Allocation Microsoft Exchange Server deployments are tightly coupled with the hardware on which they are deployed. Often, new physical servers are deployed with separate server roles for availability and reliability reasons. When administrators need to make changes (such as relocating a specific server role), the process often involves numerous configuration steps and potential downtime. A common result is physical servers that are under-utilized, leading to higher hardware, data center, and operational costs. Meeting Storage and Network Requirements In order to create a successful Exchange Server deployment, IT departments must be sure that their storage and network infrastructure is able to support their organization s requirements. Specific design details should be based on estimated usage patterns and historical performance data (if it is available). However, when server roles are deployed to physical servers, it is often difficult for administrators to quickly adapt to changing resource requirements. This makes the process of managing performance more challenging and can lead to higher deployment and maintenance costs. Addressing High Availability Challenges Exchange Server has been designed to meet organizations high-availability and disaster recovery requirements. Several of the server roles are directly protected by built-in Exchanger Server features such as Local Continuous Replication (LCR), Cluster Continuous Replication (CCR), Standby Continuous Replication (SCR) and Single Copy Clusters (SCC). However, true high-availability must also include the ability to protect against server failures, and downtime caused by operating system issues. In order to protect the complete end-user messaging experience, administrators must also include other critical applications and services, such as anti-virus, anti-spam, and BlackBerry Enterprise Services. Overall, IT departments should focus on the user experience, a task that requires end-to-end availability. To meet these needs, organizations often invest in heterogeneous products and technologies to protect different parts of their application infrastructure. IT staff must have the expertise to properly manage them, and fail-over and fail-back processes are often complicated and unreliable. Additionally, most high-availability 2008 Azaleos Corporation. All rights reserved. 2

3 solutions require additional server hardware, network, and storage resources. These requirements increase operational costs and add management complexity. Deployment Challenges Systems and network administrators must work together to ensure that their Exchange Server deployments meet business and technical requirements. Details include planning for WAN bandwidth consumption and deciding on the ideal distribution of server roles based on capacity and performance needs. The configuration process often involves numerous steps, especially when high-availability features are required. This can make deployment time-consuming and can require a high level of Exchange platform expertise. When deploying to physical servers, it is often difficult to make configuration changes or to move server roles to meet new and evolving needs. Using Virtualization to Improve Server Deployment and Operations IT departments can address Exchange Server management challenges through the use of virtualization. Running Exchange Server from within virtual machines simplifies all fo the issues listed in the previous section -- deployment, management, protection of critical server roles, and cost reduction. Table 1 provides a comparison and overview differences between deploying Exchange Server on physical servers vs. virtual machines. Management Challenge Physical Server Virtual Machines Deployment Requires the provisioning and configuration of a minimum of 4 physical servers Administration Configuration changes can be difficult and can require downtime High- Availability and Disaster Recovery Different approaches are required to protect hardware, OS s, services, applications, and Exchange Server roles Supports rapid deployment on just 2 physical servers Administrators can easily reconfigure or move VMs based on resource requirements Consistent methods of data protection for all areas of the application P2V conversions can be used for Data Center Costs Multiple physical servers are required for high-available and Simplifies server and storage consolidation performance Generally requires dedicated shared storage or local storage for each server Table 1: Comparing Exchange on Physical vs. Virtual servers Server and Storage Consolidation Many organizations have realized the efficiencies that can be gained by consolidating under-utilized workloads on a smaller number of physical servers. Virtual machines allow this capability by creating isolated environments in which heterogeneous operating systems can run concurrently. This is an ideal solution for administrators of Microsoft Exchange Server because Exchange Server typically does not require the full CPU or memory capabilities of an entire server and therefore lends itself well for combinations with other Exchange Server roles. Administrators can meet availability and performance requirements through the distribution of Exchange server roles and other workloads on a smaller number of servers. This leads to higher overall resource utilization and a decreased need for data center assets. Other types of applications and services can also be run on the same physical system Azaleos Corporation. All rights reserved. 3

4 Virtualization also provides administrators with the ability to consolidate storage resources. In simple configurations, multiple VMs can share the same local hard disk arrays. Virtual hard disks can also be stored on network-based SAN or iscsi-based devices. However, the SAN-based storage consolidation improvements will not be realized by companies following Microsoft s DAS storage migration recommendations. Overall, the flexibility provided by virtualization allows IT departments to create and modify their Exchange Server deployments to meet changing needs while minimizing overall costs. Simplified Administration Virtualization provides a tremendous advantage in the areas of data center flexibility and agility. Because virtual machines are not tied to the physical hardware on which they are running, systems administrators can easily reconfigure and move VMs as requirements change. The process of changing physical memory allocations can be performed within minutes. Other changes, such as managing CPU, network, and storage allocations are equally easy to perform in virtualized environments. This flexibility helps keep IT deployments aligned with the businesses that they support and reduces operational overhead. Implementing High Availability and Disaster Recovery Virtualization platforms provide administrators with a consistent method of implementing highavailability for all of their applications and services. The result is end-to-end protection against hardware, operating system or application failures without the complexity and overhead of managing heterogeneous approaches and solutions. When a failure occurs, a virtual machine and its associated state information can be quickly and automatically moved to another server. The fail-back operation is just as simple administrators need only specify to which physical host server the VM should move. Because VMs are self-contained, administrators need not worry about potential hardware compatibility issues or risky reconfigurations of the infrastructure. Virtualization-based high-availability features can be used along with or instead of Exchange Server s native high-availability methods. Organizations can also use the physical-to-virtual (P2V) conversion process to simplify disaster recovery and to reduce overall server costs. In this approach, production applications run on physical servers. Administrators can reduce hardware requirements at the backup site by storing virtual machine images of these systems on fewer servers. They can then use Exchange Server s replication features to keep the backup site up-to-date and to minimize data loss in the event of a failure. Reducing Overall Costs IT organizations are often asked to provide increased service levels with stagnant or decreasing budgets. Virtualization is an ideal technology to reduce operating costs through efficiency. As mentioned earlier, server consolidation can lead to increased hardware resource utilization. Data center costs related to power, physical space, and cooling are often reduced significantly. Companies should, however, identify if migration to a virtual platform will potentially require purchase of a more expensive server, thereby perhaps partially negating some of the cost reduction wins. Additionally, features such as portability and consistent high-availability and disaster recovery approaches can help streamline overall operations. Overall, virtualization provides businesses with an efficient method of deploying and managing critical application services such as Microsoft Exchange Server. Choosing a Virtualization Platform for Exchange Server Organizations have the ability to choose from among different platforms for Exchange virtualization. Azaleos has performed testing on virtualization solutions from Microsoft and VMware and has found that they are both strong options for virtualizing Exchange. This section provides an overview of when the use of virtualization is appropriate and provides details for evaluating the available platforms Azaleos Corporation. All rights reserved. 4

5 Making the Virtualization Decision One of the first decisions that organizations should consider is whether virtualization is an appropriate solution for their Exchange Server infrastructure. Although there are significant benefits of running Microsoft Exchange Server within a virtualized environment, this solution might not be appropriate for all deployments. The primary consideration is that of performance. All virtualization layers will add some amount of resource overhead particularly for an IOPS (input/output operations per second)-intensive application like Exchange (testing by Azaleos has shown that virtualization overhead results in approximately 10 15% reduction in performance). And, by running multiple workloads on the same server, the risk of exceeding resource limitations during peak load can be higher. Companies should first consider expected scalability requirements for their Exchange Server deployments. If specific server roles are expected to fully utilize the resources of a physical server, then virtualization might not be recommended. Other considerations include the expected storage performance requirements, usually summarized by the number of I/O operations per second (IOPs). Consistently high IOPs requirements are often met through network-based storage, which can be deployed with or without virtualization. Also, the new Unified Messaging role in Exchange 2007 is not supported for virtualization so companies looking to implement this functionality will need to steer clear of virtualization. Finally, servers that support a very large number of mailboxes might not be ideal candidates for virtualization due to storage-related overhead. Assuming that specific performance or configuration requirements do not preclude virtual deployments, organizations should consider the advantages of deploying Exchange Server within a virtual infrastructure. At present, however, Azaleos recommends that companies do not attempt to run more than 3,000 users on any given virtualized Exchange Server. Support Details: Running Exchange Server in a VM Azaleos has assisted many companies with successful deployments of Exchange Server within a virtualized infrastructure. Microsoft officially supports (see the following Microsoft TechNet article -- environments which choose to run Exchange within a VM, as long as the platform is either Hyper-V Server OR a third party virtualization platform (such as VMware) which has been certified by Microsoft as part of their Virtualization Validation Program. In spite of this lack of complete Microsoft validation, the lion s share of organizations who are currently running Exchange on a virtualized platform, are doing it on the VMware platform. This configuration has received extensive testing and real-world validation by Azaleos, VMware, HP, EMC and other vendors. Evaluating VMware ESX Server VMware s ESX Server platform is a complete, high-performance foundation for building a virtualized infrastructure. It runs directly on server hardware and allows for hosting numerous VMs on a single physical host server. VMware ESX Server support the most common types of production server hardware and provides access to SANs and network-based storage. VMware Infrastructure 3 (VI3) provides features that can help manage resource allocation, backup and recovery, disaster recovery and high-availability. Evaluating Microsoft Hyper-V Server Microsoft s virtualization platform, Hyper-V, is available as a server role for the Windows Server 2008 platform and as a stand-alone virtual server option. The Hypervisor itself runs directly on server hardware and creates independent parent and child partitions in which isolated VMs can be created. Selecting the Right Platform While both Microsoft Hyper-V and VMware ESX Server are capable products that can be used to support Exchange Server, they do have different strengths. Overall, VMware s product has a larger installed market base and is generally considered to be the more mature virtualization product. Additionally, VMware specifically supports the deployment of Microsoft Exchange Server on the ESX platform and has 2008 Azaleos Corporation. All rights reserved. 5

6 invested a lot of testing and development resources to ensure that this configuration is optimized. Drawbacks include more complicated deployment processes (e.g. separate product from core Microsoft OS) and higher costs for supporting ESX Server and VI3. Microsoft Hyper-V is simple to deploy and is available for no additional charge whether purchased as part of the Windows Server 2008 platform OR as a stand-alone server option. It offers a high degree of compatibility with device drivers on the Windows platform and management tools that will be familiar to Windows systems administrators. For Hyper-V, the only major drawback centers on its lack of maturity (i.e. newer platform released in its initial version). Azaleos and the OneServer Virtualization Solution Azaleos is an expert in the monitoring and management of Microsoft Exchange Server in a wide variety of different best practice configurations. Azaleos supports and has deep experience with on-premise Exchange deployments for both physical and virtual systems. Post deployment the Azaleos Network Operation Center experts then remotely monitor and manage the messaging systems for the customer. OneServer Virtual Edition, the Azaleos virtualization offering, is designed to run Microsoft Exchange Server within a virtualized environment to reduce costs and to simplify administration. ViewXchange, the Azaleos remote monitoring service, actively monitors both the host AND the guest servers on the virtual platform to provide a full picture of the health of the entire system. Figure 1 provides an overview of a recommended high-availability deployment of Microsoft Exchange Server. Figure 1: Azaleos OneServer Virtual Edition Deployment Configuration The complete configuration requires only two physical servers, but still meets high-availability and scalability requirements by relying on clustering and network-level load balancing. Azaleos OneServer Virtual Edition initially shipped in early 2008 with support for VMware ESX but has now recently been updated to also support Microsoft Hyper-V Server. In addition to the software, Azaleos focuses on best practices for implementing and servicing Microsoft Exchange Server in a virtual environment. Overall, by using Azaleos OneServer Virtual Edition, IT departments can realize the full benefits of the Microsoft Exchange Server with reduced costs, simplified administration, and high levels of data protection Azaleos Corporation. All rights reserved. 6