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Getting Better Performance for Your Virtual Machines

As a seasoned virtualization expert (mostly with Hyper-V environments), I totally agree with the concept of building your VMs (virtual machines) and virtualization hosts to meet a particular need.

Often, I talk to SQL DBAs (database administrators) or Exchange administrators who swear that these platforms can NEVER be virtualized. This line of thinking is so wrong that Microsoft itself has bet their business around it (e.g., Office 365, Microsoft.com, etc.).

The most important piece of advice I give to virtualization newcomers is to treat a VM like you would a physical server. If a physical Exchange server needs 16GBs of memory and 4 CPUs, then building a VM with only a single virtual processor and 2GB of memory is going to result in a bad user experience, obviously.

HDD (hard disk drive) performance is always a concern with VMs. If you are creating a VM to run a disk intensive SQL server, then you will certainly care about your disk performance. With the more recent versions of Hyper-V, there is little noticeable performance reduction when choosing dynamically expanding VHD (virtual hard disk) vs. using a fixed size VHD. The big downside is that you now have to monitor and manage your storage on the host since your VMs can quickly consume physical space.

If extra disk performance is really needed, there is an option of using a pass-through disk. Pass-through disks will use an unused volume on the physical Hyper-V host as if that volume were its own. With pass-through disks you’ll get true hardware-level performance. The downside is that your VM is now tied to this physical storage making it difficult (or impossible) to migrate to a different host… so plan accordingly.

 

 

About the author

Robert Borges

About Robert...

I have been in the IT industry since 1993 focusing mainly in networking. Though I got an early start as an amateur computer enthusiast, and wrote my first database app at age 12, I started my professional career working in the MIS department of one of the largest liquor distributors in the northeast. I started out there as a systems operator on the company’s two mainframe systems. From there I moved into PC support, and help design and implement the company’s first client-server network… This was back in the days of Win NT 3.51. I also worked on my first migration to NT 4.0 back then.

From there I went on to work with Novell 3.x and 4.x along with Windows domains and active directory environments. Working my way up from technician, to specialist, to administrator, and eventually all the way up to Sr. Engineer. I spent many years working for consulting firms, 9 of which I owned and operated my own firm.
Over the years, I have worked with (at an expert level) various versions of: Windows client and server operating systems (including Windows 7 and Windows Server 2008 R2);various virtualization technologies (Hyper-V, Virtual Server, Virtual PC, VMware, etc…); MS-SQL server 6.5- 2008 R2; Exchange 4-2010, and much more.

I am now Director of Information Systems at Bay State Integrated Technology focusing on cloud computing and IT service, with expertise in: IT Infrastructure & Architecture, IT Security, and Cloud Computing platforms & technologies (SaaS, PaaS, and IaaS).

I am in a constant state of learning about new products, and new versions of products. Many of which we end up implementing in lab environments and sometimes for our clients. I have a pretty broad range of expertise and experience. It is my goal to share some of this experience on this blog to help enrich the IT community.

Permanent link to this article: http://www.robertborges.us/2013/05/virtualization/getting-better-performance-for-your-virtual-machines/

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