Deciding which applications in the data center should be virtualised is an important process, says Alexey Strygin, Senior Solutions Architect, Veeam Software, Middle East
Virtualisation is one of the hottest tech trends today. While it is a proven technology, it becomes a debated topic on whether or not to virtualise every application in the data center. Those in favour believe that virtualisation will only enhance capabilities and bolster efficiencies – and can deliver features that aren’t possible within a physical-only world. There are a lot of critical applications that have not been virtualised yet however. This is the debate for today and in to the future for the most critical and largest workloads, for many organisations that largest workload is Exchange.
Email and communication services are the central nervous system of many organisations. As such it is widely accepted as the most critical application for companies today. There are a lot of benefits to virtualising Exchange Server, especially when considering flexibility and scalability features. However, the key to successfully running a virtualised Exchange environment is to understand that running VMs at their limits requires the additional effort of regularly tweaking and tuning them. Further, given that virtualisation technologies are very mature and can scale very high; companies can make informed decisions on how to virtualise Exchange Server. Years ago, early adopters surely had learning challenges along the way. In 2014 and beyond, companies are clearly able to identify the benefits of a virtualised server:
That was then: Virtualise to effectively utilise hardware
When our virtualisation practice became serious; we moved beyond the paradigm where dedicated physical servers were not fully utilised. Companies that run Exchange on dedicated physical servers saw that memory or CPU on average consuming less than 10% of their capacity; thus the hardware would be able to take much more load than is currently put on the servers. That was the way Exchange was designed years ago; and for the time, it was successful. But virtualising the critical Exchange Server may take a different approach… The issue is that an Exchange Server designed to host 2,000 mailboxes; yet only runs 200 mailboxes is actually a bad design. Too many times these designs are delivered because there was not enough research to determine what should be provided. This can more correctly utilise rack space, cooling and power, and it also avoid over purchasing of server maintenance costs. We know that virtualisation allows you to better utilise your hardware, now we relate it to the specific points where it may help us with Exchange.
Virtualising Exchange allows you to place it along with other virtualised applications on one server to save power, cooling and rack-space in your datacenter. This allows you to reduce the costs of hardware because you utilise the hardware more effectively by combining many VMs on a single physical server rather than spreading the applications over many servers. Many supporters of virtualisation characterise these combined benefits as “green IT.”
Exchange is important. Can we dynamically adjust resources?
Virtualisation enables you to dynamically allocate resources such as memory or CPUs to your VMs. You can increase or decrease resources such as memory or CPUs on your VMs on demand. When your company’s requirements for messaging change, you can adjust the CPUs or memory so the virtual Exchange servers can handle the load. To allocate resources when running physical Exchange servers, you normally add resources by adding storage or memory to your server, or you purchase another physical server. In addition to having to go through a lengthy procurement process to purchase and install the hardware, you also have to create database copies and move mailboxes between databases. When you are adding up to a hundred mailboxes to your existing Exchange environment, then dynamically adjusting resources for your virtual Exchange server does the job very well, without much effort for the administrator and without much additional cost.
If you plan for physical Exchange servers, you need to make sure that your servers are sized in a way that considers peak periods and future company growth. Using virtualisation, you can base resource allocation on your current needs and then dynamically allocate resources when your company’s messaging users require it. Take care when virtualising Exchange’s systems that support a large user base. Systems with more than 5,000 users might not be suitable candidates for virtualisation, and systems with 3,000-5,000 users should be monitored closely to be sure they perform well when virtualised.
Can Exchange provide robust application availability when virtualised?
Many SMEs run all Exchange roles on a single physical machine because using a Database Availability Group (DAG) requires another machine and thus would be more expensive because of the extra hardware and licenses required. Using virtualisation allows even SMEs to create a DAG and replicate their databases to multiple disks. This of course increases availability in the event of system outages and also allows you to patch your Exchange system without affecting users. Exchange server 2010 or 2013 running on Windows Server 2012 allows you to use the Standard Edition of Windows, thus providing DAG functionality without extra Windows license fees. With a DAG, you can have database copies on another Exchange server. The minimum requirement for a DAG is two Exchange servers, but you can add as many as 16 Exchange servers to a DAG.
Virtualisation should also be considered if a company wants to use physical servers for its main datacenter and plans to have a second disaster recovery datacenter. The benefit of virtualising Exchange at the disaster recovery site is being able to run a multi-site DAG without deploying a lot of hardware in the disaster recovery location. The best option is to implement a virtual infrastructure with at least two host machines, and make sure the Exchange VMs do not run on the same physical host at the same time. The takeaway here is that virtualising Exchange Server provides more options to the application than what is provided when Exchange is not virtualised. When it comes to the larger picture of availability, companies should have as many options in the realm of application availability as possible.
Exchange needs robust protection
Virtualisation provides several benefits in the area of backup and restore, allowing you to quickly back up your server and also quickly recover messages, databases and even complete servers. In fact, some recovery options are only available when Exchange is virtualised. To successfully back up Exchange Server, you need to use an application-aware backup solution such as Windows Backup. Windows Backup uses Volume Shadow Copy Service (VSS) in Windows to ensure your Exchange databases are cleanly prepared to a ready state for backup. Otherwise you might not be able to mount the database and data would be lost.
You need a backup solution that is Exchange aware and capable of VSS to back up and restore Exchange Server databases. A restore from a VM is much quicker than from a physical machine because you can restore the backup directly on the same or another host system. It takes more time to restore a physical machine because you not only need to set up the physical machine from scratch but also recover the data—and this takes many hours if the data is stored on tape drives—or present the recovered databases to the physical machines using quite expensive SAN software.
Virtualising Exchange offers a flexible test environment
Another reason to virtualise that applies to organisations of all sizes, is to virtualise test environments. A virtualised test environment provides flexibility that allows you to add or remove servers very quickly and also to change the complete environment. With virtualisation, you can easily clone the production environment into the test environment so you can get the real domain controllers (DC) and Exchange servers in the test environment, and this makes any testing much more realistic. You can create a complete, isolated Exchange environment, and then you can start it up and use it as your test environment. Remember, a virtual environment consists only of files, so you can quickly and easily grab them and use them on another host machine. So virtualisation means portability. This can make the process of going about critical upgrades of Exchange Server (or the supporting Active Directory environment) a clear and concise process. The notion of a virtual lab allows for item level recovery, sandboxing and application testing to be performed in an isolated network. This is a great way to verify recoverability of virtual machines as well as prepare for critical changes with confidence.
It is 2014: Let’s virtualize Exchange Server
The reality is that companies should not need to be convinced that virtualising data center workloads is a good idea in 2014. The challenge companies face is that the most critical applications, such as Exchange, may not have been virtualised yet due to fear, cost or even prior investment in a physical deployment. The resources are there. Best practices have been made. Now is the time to realize the benefits of virtualising Exchange.
