I appreciate individuals and organizations who back up their claims with quantifiable evidence. That's one of the many reasons I admire Condusiv Technologies, also the makers of the industry standard Diskeeper and SSDKeeper for PCs. In fact, I encourage you to download their free I/O Assessment Tool and run it on a few of your production VMs. The interface is in the next figure.
I suggest you run the tool long enough to get at least 5 days of production data to be analyzed by that tool. After collecting data from servers you want to monitor over 5 days, the tool crunches the data and provides a report that identifies which systems suffer from the severe I/O inefficiencies that can be easily solved by V-locity and which don’t.
I know from personal experience that I have a much better chance of getting IT purchases approved if I can provide hard numbers that substantiate my arguments.
The problem and how V-locity solves it ^
According to Condusiv's and third-party research, your I/O-intensive VM workloads (particularly databases) have a complicated data path to reach the underlying physical storage.
Take a look at the following diagram I made for you; Condusiv calls it the "I/O data blender effect":
The idea here is that all of those abstraction layers (especially at the host level) randomize the VM I/O streams, which slows both read and write operations at the storage layer.
This randomization from virtualization and severe inefficiencies in the hand-off of data from the Windows OS to underlying storage means VMs run approximately 50 percent slower than they should due to this "death by a thousand cuts" scenario according to Condusiv.
Now let's examine another diagram, this one showing how V-locity I/O reduction software solves the problem.
Specifically, V-locity is a thin, kernel-mode file system driver that resides on each VM and fields I/O traffic to and from that VM. As you can see in the diagram, V-locity optimizes the size of data blocks and their frequency, resulting in a potentially significant performance boost on your VMs.
V-locity basic operation ^
Install V-locity on your Windows Server VMs—I didn't find this point obvious on the Condusiv web site. You see the software in three locations:
- A service named V-locity
- A notification icon running in the system tray
- A lightweight web control panel (shown in the next figure)
The purpose of the web control panel is to configure V-locity driver features and display performance statistics. With regard to the former, we should review the underlying technologies that enable V-locity to do what it does on your VMs.
IntelliMemory is V-locity's read I/O optimization engine. In short, IntelliMemory dynamically uses your virtualization server's RAM as a cache to store "hot," frequently accessed data. It only uses memory that is otherwise idle and available so there never an issue of memory starvation. 4GB of idle DRAM commonly serves 50% of read traffic.
I hope it makes sense that reading data directly from a memory cache is exponentially faster than doing so from disk. What's cool here is that IntelliMemory respects your VM's current RAM allocation; it "backs off" usage if the application or other processes ask for more memory.
IntelliWrite is V-locity's write I/O optimization engine. Specifically, IntelliWrite provides pre-allocating intelligence to the Windows OS, so it can write files in a more sequential manner, which requires fewer I/O operations to write or read any given file. A related Condusiv technology called InvisiTasking ensure this background task runs at near-zero overhead to the server by only using free CPU cycles.
The bottom line is that Condusiv designed V-locity to deliver as much performance as possible while being unobtrusive to server resources and its administrators.
Centralized V-locity management ^
Of course, if you want to install V-locity on every VM, and your organization has hundreds of VMs, you'll want a centralized management tool. For that requirement, Condusiv provides the V‑locity Management Console, or VMC.
This web-based tool (shown in the next screen capture) allows you to manage V‑locity centrally across your environment, including deploying the software on VMs and aggregating performance statistics.
One note: V-locity Management Console is incompatible with Condusiv’s Diskeeper for PCs, so if you are licensed for both products, you have to use a separate Diskeeper Administrator console for Diskeeper.
Licensing and wrap-up ^
You can purchase individual V-locity licenses for $524.95 USD apiece for up to five licenses. For more than five, Condusiv requires you contact them for a volume license quote. Most opt for a host-based license if your VM density is greater than 7. A Condusiv representative can help determine what is best for you. Volume license customers get their own private web portal from which you can download the software and manage your licenses. Alternatively, you could choose to work with a Condusiv authorized reseller.
In conclusion, V-locity is software I install on all the VMs I use in my training, and I suggest it to my consulting clients as well. I make no bones about the fact that I've been a happy Condusiv customer all the way back when they were Executive Software and Diskeeper was their only product.