Wednesday, August 10, 2011

Barriers to Virtual Machine Performance

Virtual machines (VMs) have created a revolution in computing. The ability to launch a brand-new server with a few keystrokes, utilize it, and then discontinue or change that utilization, is a facility that will only grow with time. The future direction for virtual machines is probably a scenario in which a majority of computing is actually performed on VMs, with minimal hardware only present for hosting purposes.

The technologies being utilized for virtual technology are quite remarkable. They sum up to resources being coordinated and shared in such a way that work gets done across multiple platforms and environments almost as if no barriers existed at all. However, there are several issues that, if not properly addressed, can severely impact virtual machine performance.

First is addressing the issue of I/O reads and writes. If reads and writes are being conducted in the presence of file fragmentation, I/O bandwidth will quickly bottleneck. Fragmentation is the age-old problem of files being split into tens or hundreds of thousands of pieces (fragments) for better utilization of hard drive space.

In a virtual environment, fragmentation has a substantial impact, if only due to the multiple layers that a single I/O request must pass through in a virtual environment. If each I/O is performed for a single file fragment, performance is critically slowed down, and this condition can even lead to an inability to run more VMs.

In dealing with fragmentation, there is also the need for coordination of shared I/O resources across the platform. A simple defragmentation solution will cut across the production needs of VMs, simply because the effective prioritizing of I/Os is not done.

There is also a situation of virtual disk “bloat”-- wasted disk space that takes place when virtual disks are set to dynamically grow but don’t then shrink when users or applications remove data.

Although these barriers are multiple, there is a single answer to them: virtual platform disk optimization technology. The first barrier, fragmentation, is dealt with by preventing a majority of it before it even occurs. Files existing in as few fragments as possible means I/O reads and writes are occurring at maximum speed. Resources are also coordinated across the platform so that VM production needs are fully taken into account.

Such software also contains a compaction feature so that wasted disk space can be easily eliminated.

These barriers can frustrate the management of virtual environments. Fortunately, IT personnel can solve them with a single virtual machine optimization solution.

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