Case Study: Exchange 2007 on VMware and NetApp

There are a lot of tangible benefits to running Exchange in a virtualized environment rather than a physical one, but while a lot of people are evaluating such solutions, it seems that many still remain skeptical about performance and reliability.

My company, Unity Builders Group (UBG), has run Exchange in a virtualized environment for a while now. We recently went through a migration to Exchange 2007 and VMware® VI3, and we are extremely pleased with the results. Tech OnTap asked me to describe the migration process and the advantages of running Exchange 2007 on VMware and NetApp® storage.

Migration to VI3 and Exchange 2007

A year and a half ago, we had roughly 300 mailboxes on Exchange 2003. Since then we’ve grown to about 450 mailboxes (seats). While that’s not big in absolute numbers, it represents 50% growth in our Exchange environment (and other associated infrastructure) over a relatively short time frame.

Our Exchange 2003 server was originally hosted on a VMware server running ESX 2.5, while our other VMware servers were running ESX 3.0.1. Our NetApp environment was and still is on the FAS270 model appliance. Because Exchange 2003 was hosted on ESX 2.5, we were unable to benefit from the advanced features of VMware Virtual Infrastructure 3 (VI3) such as VMotion®, DRS (Distributed Resource Scheduler), or HA.

At the same time, our Exchange 2003 server was in need of a rebuild, and I needed to allocate more storage for Exchange data stores. Since Exchange 2007 was shipping and seemed to offer some significant benefits over Exchange 2003, we opted to migrate to Exchange 2007.

Since Exchange was already virtualized and delivering good performance, we started by upgrading the VMware server hosting Exchange to ESX 3.0.1 like the other two servers. This also gave us the opportunity to rebuild the server to accommodate increased space requirements based on the growth we were experiencing.

From there it was a natural progression to move to Exchange 2007. Because Exchange 2007 is less I/O intensive than Exchange 2003, it is actually better suited to virtualized environments than Exchange 2003.

Exchange 2003	Exchange 2007
32-bit Windows®	64-bit Windows®
900MB database cache	Multi-GB database cache
4Kb block size	8Kb block size
High read/write ratio	1:1 read/write ratio
Storage is common pain point	Eliminates storage pain point

Table 1) Comparison of Exchange 2003 versus 2007.

At this point, we started by doing our homework; we watched Webcasts, read books, and so on until we were comfortable with Exchange 2007. Next we created a few test mailboxes in Exchange 2003 and installed an Exchange 2007 server in our virtual environment. We then migrated the test mailboxes from Exchange 2003 to Exchange 2007 and tested the send and receive functions both internally and externally.

Once we felt comfortable with the success of these test migrations, we proceeded to migrate the mailboxes of our IT staff. When we felt our Exchange 2007 environment was working 100%, we began the migration of the remaining active users, migrating 400 to 450 users over a two-week period.

For those who might not be aware, Exchange 2003 and 2007 can coexist together in your environment while you're performing the migration. We operated in this fashion for several weeks. You just have to do your homework and make sure you don’t leave any bases uncovered.

The only real problem we ran into as a result of the migration was that we forgot about our scanning to e-mail functionality. When we finished migrating all mailboxes and public folders to Exchange 2007, we shut down Exchange 2003. As a result, all scan to e-mail jobs went into limbo; people were no longer receiving their scans. This was easy to resolve; the lesson is to be sure you map absolutely everything that depends on your e-mail systems.

Advantages of the New Environment

VMware Advantages
We currently have three ESX servers, all now running ESX 3.5. To support our Exchange 2007 environment as well as a busy Citrix environment, we utilize a combination of VMware VMotion, DRS, and HA. These tools dramatically increase our flexibility and decrease the time it takes to deploy new servers.

VMotion allows us to migrate virtual machines (VMs) from one server to another without interrupting service. For example, if I need to do a BIOS update or other firmware update on a server, I can migrate all the VMs off of that server and take the server down for the upgrade without the users even noticing that anything has happened.

Figure 1) VMotion.

VMware DRS gives us automatic load balancing across our ESX servers so that we get optimal utilization such that a server is never overloaded or underutilized. VMware HA protects us by automatically restarting VMs on other servers should an entire ESX server fail.

Figure 2) VMware DRS uses VMotion to automatically migrate VMs to balance load. VMware HA automatically restarts VMs on another server if a physical server fails.

One unique thing we’ve done in our environment is to create a rule that keeps the VMs that run our Exchange 2007 mailbox server, our hub and client access server, our Symantec™ Enterprise Vault™ Archive server, and our BlackBerry server on the same ESX server. That way all the communication that occurs between those servers actually happens on the virtual switch within the ESX server and doesn’t traverse our physical network switches.

NetApp Advantages
On the back end, we use a NetApp FAS270 storage system with 3TB of storage capacity. The NetApp system was installed with the assistance of our partner, Long View Systems, an IT services provider with over 400 technical consultants and offices in Calgary, Edmonton, Vancouver, Denver, Dallas, and Houston. We work with Long View not only because of its technical expertise, but also because of its ability to analyze our business requirements and propose solutions that we can afford and manage today that won’t paint us into a corner when it comes time to expand in the future.

The best practices for Microsoft® Exchange suggest using RAID 10 (striping and mirroring) for back-end storage. However, mirroring—which requires double the storage capacity—was an expensive option for us. NetApp gave us the ability to use RAID-DP® to provide the high I/O performance required by Exchange at much less cost without sacrificing resiliency. In fact, NetApp’s Double Parity RAID implementation actually provides better resiliency than RAID 10. RAID-DP is 163 times less likely to lose data than RAID 10 and 4,000 times less likely to lose data than RAID 5.

	RAID 5	RAID 10	RAID-DP
Cost	Low	High	Low
Performance	Low	High	High
Resiliency	Low	Med	High

Table 2) Comparison of RAID 5, RAID 10, and NetApp RAID-DP.

Our ESX servers have Fibre Channel HBAs, which connect them to our NetApp storage system. While we’re using Fibre Channel today, one advantage of the NetApp approach is that we can add NAS protocols (NFS and/or CIFS) and iSCSI in the future if we need to, all on the same storage system.

NetApp provides close integration with both Exchange and VMware, which can make the life of an administrator a lot easier. I recently participated in a NetApp TechTalk in which the specifics of many of these technologies was discussed. That gave me the opportunity not only to talk about what UBG was doing, but also to hear a lot more about NetApp and VMware solutions.

NetApp’s integrated Snapshot™ technology makes it easy to capture consistent, point-in-time images of Exchange data for backup, and it puts the backup workload on the storage system rather than on Exchange servers.

Snapshot is the foundation technology on which NetApp builds a variety of related services. For instance, NetApp SnapManager® for Exchange integrates with Exchange to coordinate actions between the Exchange server and storage to create backups that are consistent and fast. NetApp SnapManager for Virtual Infrastructure provides a similar capability to back up running VMware virtual machines. Because backups occur very quickly and put no load on ESX servers, you can create many more backups per day for greater data protection.

For disaster recovery, NetApp SnapMirror® technology builds on NetApp Snapshot to create a simple and reliable mechanism for asynchronous replication to a remote site. Unlike many other replication solutions, SnapMirror allows you to have different storage infrastructures at your primary and remote sites. You can use Fibre Channel HBAs at one and iSCSI at the other, and you can use faster but more expensive Fibre Channel disks at your primary site and less expensive SATA disks at your DR site.

Figure 4) NetApp SnapMirror provides flexible replication for virtualized environments.

NetApp also offers deduplication technology that works with your primary storage (rather than just on backups) to eliminate duplicate copies of blocks and reduce the amount of storage you need. This deduplication technology works particularly well in virtual environments because virtual machines are typically almost identical and thus have a large amount of duplication. The storage savings you get from deduplication of your primary site gets passed along to your DR site, reducing the storage needed there.

Figure 5) When NetApp deduplication is used at a primary site, the space savings are automatically passed on to the DR site.

NetApp has worked closely with VMware to integrate the features of SnapMirror with VMware Site Recovery Manager (SRM), a new tool from VMware that simplifies DR planning, implementation, and testing for virtual environments. (A companion article in this issue describes the integration of NetApp and VMware technology in SRM in more detail.)

Conclusion

The combination of VMware and NetApp technologies with Exchange 2007 has been a real win for us. Virtualizing our Exchange environment gives us greater reliability and flexibility with good performance. VMotion lets us move virtual machines easily for maintenance or other needs. DRS makes sure that Exchange servers are always properly resourced. VMware HA makes sure that Exchange and other important services get restarted right away should an entire ESX server fail.

NetApp storage is a good match for the capabilities of VMware, offering greater reliability at a lower cost than mirroring. We haven’t yet implemented all of the NetApp capabilities I’ve described above in our environment, but having a range of options will give us flexibility to meet our needs. We intend to look seriously at implementing VMware SRM using NetApp SnapMirror in late 2008 to provide greater protection for both our Exchange and Citrix environments.

Joe Jerebic Information Systems Manager Unity Builders Group As IS manager of a dynamic company, Joe is responsible for maintenance and support of much of the IT infrastructure, including Citrix and Exchange running under VMware, Cisco network infrastructure, business continuity, and DR. Prior to joining UBG, Joe served as a technical consultant with a large IT firm specializing in VMware implementations. He is a Microsoft Certified Systems Engineer (MSCE) and VMware Certified Professional (VCP).