E-Guide Advice for Virtualizing Exchange 2010 Server Roles When virtualizing Exchange Server 2010, it's important to correctly configure virtual machines (VMs) that will host certain Exchange Server roles otherwise a few gotchas will surface. For example, you'll need to assign the correct number of processors to the appropriate amount of RAM. This tip gives more advice for correctly configuring VMs for optimal performance. Sponsored By:
E-Guide Advice for Virtualizing Exchange 2010 Server Roles Table of Contents Exchange mailbox protection explained Resources from IBM Sponsored By: Page 2 of 9
When virtualizing Exchange Server 2010, it's important to correctly configure virtual machines (VMs) that will host certain Exchange Server roles otherwise a few gotchas will surface. For example, you'll need to assign the correct number of processors to the appropriate amount of RAM. This tip gives more advice for correctly configuring VMs for optimal performance. Client access and hub transport servers Even in small Exchange environments, the Client Access Server role and the Hub Transport Server role are commonly collocated with the Mailbox Server role on a single computer. For organizations with tens to hundreds of mailboxes, this is an all-in-one configuration. Resource requirements for the CAS are usually less than what the hub transport server traditionally needs. Since every piece of mail in an Exchange Server 2010 organization flows through the hub transport server -- for routing and messaging policy application purposes -- it bears a heavy load. Microsoft states that each role should be given a minimum of 2 GB of RAM, with a recommended setting of 1 GB per core for the hub transport server and 2 GB per core for the client access server. Comparative requirements for the client access server can be larger in environments that heavily rely on Outlook Web App (OWA). As a rule, virtualization environments work best when VMs are configured with the smallest number of processors possible. The processor power requirements of your Exchange 2010 environment will determine that number. Starting small and working up is the best rule of thumb. Microsoft suggests eight cores for the hub transport server and four cores for the client access server to support an organization of several mailbox servers and thousands of mailboxes. Organizations with fewer mailboxes and lower levels of non-mapi client traffic could start with as few as two cores. Sponsored By: Page 3 of 9
Edge transport servers Edge transport servers typically consume lower levels of resource utilization. This level can depend on the rate of inbound and outbound mail flowing through your Exchange organization, along with your level of rejected mail. If your organization deploys spam filtering from an upstream provider, this reduction in traffic can affect edge transport resource utilization. Microsoft also suggests configuring edge transport servers with a single processor core and up to a maximum of 12 cores -- if your virtual platform will support them. RAM requirements start with a minimum of 2 GB with 1 GB per core. You can always add more memory later if you experience excessive paging, poor performance or an email build-up in messaging queues. Unified messaging servers This is easy -- don't virtualize unified messaging servers. Microsoft does not support them. Unified messaging servers require substantial processing power and have little tolerance for processing latency. Microsoft's suggestion for even a small Exchange organization is a minimum of two to four cores and 4 GB of RAM, with 2 GB per core of RAM. If you're using unified messaging, I advise that you steer clear of virtualization for now. Mailbox servers Mailbox servers are the heavy-lifters in any Exchange infrastructure; they are where resources are used in larger quantities. You might want to consider virtualizing mailbox servers last. While they can be virtualized, they require careful evaluation before beginning. Experience gained from virtualizing Exchange's other less-challenging roles will help. Microsoft states that a four-core mailbox server should be able to support several thousands of mailboxes. The RAM recommendation for that server starts with 4 GB of RAM plus an additional 3 to 30 MB per mailbox. Virtualizing any mailbox server will consume a large share of your virtual host's available RAM resources, so plan accordingly and don't oversubscribe your virtual infrastructure. Sponsored By: Page 4 of 9
Exchange Server 2010 virtualization gotchas Exchange Server organization's mail usage characteristics have more to do with these calculations than any RAM or core numbers suggested here. Measuring your existing metrics on physical servers is the first step in preparing to virtualize Exchange Server. Measured over time, those metrics are necessary to determine your starting points for processor and memory resource assignment. Microsoft states that relying on someone else's numbers is a flawed assumption. In Understanding Server Role Rations and Exchange Performance, Microsoft notes, "A significant percentage of the server processing is associated with the overhead of analyzing connections and scanning accepted messages. For this reason, it's not possible to provide a sizing metric based solely on the number of messages sent and received per second." While this quote relates specifically to the activities within the edge transport server, it's also good advice for the other roles. If you don't correctly determine a baseline for your Exchange 2010 server role performance before you begin a virtualization project, any or all of the roles may cause trouble. Sponsored By: Page 5 of 9
Exchange mailbox protection explained As an IT administrator, you need to protect Exchange data. Typically, this means protecting every mailbox -- the personal database that stores each user's mail items (Inbox, Outbox, Sent Items, etc.), as well as its calendar, contacts, tasks and other user-created folders. Let s take a look at some of the issues surrounding Exchange mailbox protection. Problems with unprotected Exchange mailboxes The loss of an email thread -- or even a single email -- can delay productivity and cause confusion. An email may constitute an entire transaction with a customer, for example; losing an email associated with a multi-million dollar contract can be catastrophic. "Email is the very personification of true information flow within, into and out of an organization," said Andy Grogan, Exchange Server MVP and head of IT for Hounslow Homes in the U.K. "[Email] can be as binding as a paper contract." That underscores the legal and regulatory aspect of email. Virtually all businesses are subject to regulatory mandates that obligate email retention and ensure timely discovery during litigation. A lost mailbox or even a single lost email may cost you a court case, or expose the business to significant fines or other crippling penalties. Options for protecting Exchange mailboxes There are numerous options available to protect Exchange mailboxes, such as Exchange Server 2007 s cluster continuous replication feature. CCR performs asynchronous updates for a second copy of the email database once changes take place in the active copy. If a problem occurs with the active database or server, email can failover to the secondary (clustered) server and database. In Exchange Server 2010 Microsoft replaced CCR with more robust database availability groups (DAGs), which allow up to 16 Exchange 2010 mailbox servers to support automatic database-level recovery in the event of failure. Exchange Server 2010 DAGs also introduce a lagged database feature that replicates the mailbox after a period of time. This provides a Sponsored By: Page 6 of 9
window that enables message recovery up to 14 days before synchronizing with other database copies. The advantage here is that a message accidentally deleted from an Outlook client doesn't immediately remove the copy on the corresponding Exchange Server. Exchange Server 2010 also supports single-item restoration, allowing administrators to recover deleted email without restoring from a backup. More conventional backup tools include Volume Shadow Copy Service (VSS), which is often used with older versions of Exchange Server. More recent tools include Exchange streaming backup and restore capabilities, which support target entire storage groups and individual databases within them. Other backup tools include Microsoft's System Center Data Protection Manager and thirdparty backup tools like BackupExec. "Those [tools] both work in a traditional backup model where you're copying from a server to a backup tape [or disk]," said Mike Crowley, Exchange MVP and enterprise infrastructure architect with Planet Technologies, Inc. "Your data is stored in a separate location that may be offline in a protected environment. If something happens to the primary environment, you can revert back to that." A wide range of email-archiving products, such as Symantec Enterprise Vault and Athena Archiver, can archive email content to a storage subsystem for quick recovery or legal discovery. There are also storage appliances dedicated to email archiving and recovery including the Fujitsu Services Archiving Appliance, Jatheon Technologies' Plug n Comply email archiving product and the ArcMail Defender Email Archiving Solution, among others. Traditional storage backup capabilities like SAN snapshots can be used to protect Exchange mailboxes, but experts warn that Microsoft may not fully support snapshots from Exchange Server roles installed on virtual machines. Microsoft support is often an essential part of Exchange Server deployment, so some organizations opt for traditional backup or replicated clustering techniques. Sponsored By: Page 7 of 9
It s possible and less risky to combine backup techniques to protect Exchange mailboxes. There s no reason why you can t use CCR, database availability groups, VSS backups, vaulting and SAN snapshots as part of a highly resilient environment, Grogan noted. Making the most of Exchange mailbox protection Exchange Server 2010 SP1 allows you to separate the user's primary mailbox from his personal archives. Experts agree that organizations that allow users to create personal archives should keep both archives separate. The principal advantage of separating the databases is that you don t have to back up personal archives as frequently. The archives can also be moved to a lower, less expensive storage tier than the user's primary mailbox, which demands frequent tier 1 storage access for best performance. However, backup options for personal archives and the primary mailbox are identical. Exchange Server 2010 is tightly integrated with Active Directory; an AD failure can cripple Exchange -- no matter the level of protection. Grogan reminds administrators to also back up Active Directory at least nightly. Platform migration can seriously affect mailbox protection. Mailbox backups created for an older version of Exchange Server are not mountable in later server versions without a deliberate conversion process. Therefore, any protection plan must include provisions for migration. In many cases, an organization may need to retain a working server with an older Exchange version in order to access older backups. Perhaps the most critical practice for Exchange mailbox protection is to test backups and restoration processes regularly. Simply verifying a backup is not enough, since a verify feature only ensures that the backup is readable. There is no way to ensure that the backup captured all of the necessary data. "Test restoration scenarios for Exchange from tape [or disk] monthly in a lab environment, which should be as close to production as possible," Grogan said. Sponsored By: Page 8 of 9
Resources from IBM Storage Efficiency Faster and easier with IBM XIV Gen3 IBM System Storage Solutions for Microsoft Technologies Webcast: Best Practices for Managing Costs in a Microsoft Exchange Server 2010 About IBM At IBM, we strive to lead in the creation, development and manufacture of the industry's most advanced information technologies, including computer systems, software, networking systems, storage devices and microelectronics. We translate these advanced technologies into value for our customers through our professional solutions and services businesses worldwide. Sponsored By: Page 9 of 9