SOURCE: Bruce Boyers Marketing Services

July 07, 2010 18:17 ET

The Primary Barrier to Virtualization Performance

BURBANK, CA--(Marketwire - July 7, 2010) -  Hardware virtualization has solved many problems in computing environments. First among these would be the advanced utilization of hardware; prior to virtualization, a new server meant new hardware, a new version of the OS and new applications. Virtualization now means that a new server is as simple as its virtual creation. It can run the same or a different operating system as the host server. It can be running the same or entirely different applications. Best of all, it can be optimized for a specific task or set of tasks that won't be competing against others for server resources.

With the rapid proliferation in the use of virtualization by enterprises, hardware manufacturers have ensured that servers could handle the load created by multiple virtual machines. CPU, network and memory resources allow for greater VM density and operation.

One barrier to virtualization performance, however, that is not addressed by hardware solutions is file fragmentation.

Fragmentation affects performance on all hard drives, but in a virtual environment carries several other issues. Because a virtual machine has its own I/O request being relayed to the host system, multiple I/O requests are occurring for each file request; this would be a minimum one request for the guest system, then another for the host system. When files are split into hundreds or thousands of fragments (not at all uncommon) it means the generation of multiple I/O requests for each fragment of every file. This action is multiplied by the number of virtual machines resident on any host server, thus much unnecessary overhead is created on the operating and file systems.

Additionally, virtual disks set to dynamically grow don't shrink when users or applications remove data. This bloats space and wastes what could be allocated to other virtual systems.

This is not the sort of problem that can be solved by a simple defragmenter. Probably the most basic reason is that a defragmenter must usually be scheduled or run manually -- today's systems are expected to remain constantly up and running and do not allow for such maintenance "windows." More to the point, however, is the fact that fragmentation in virtual environments needs to be addressed both from a host and guest standpoint, as it occurs in both scenarios.

Advanced virtualization technology requires an equally advanced solution. Today, technology exists that will alleviate the 'virtual' disk bottleneck for virtual machines and provide a faster and more efficient virtualization computing platform. Instead of defragmentation only, a majority of files are written in a non-fragmented state in the beginning. All of this occurs invisibly, in the background, optimizing performance and allowing for creation of further virtual machines without the need for adding hardware. This technology also frees up vital storage resources by eliminating virtual disk "bloat," and synchronizes the complex and ongoing activity between host and multiple guest operating systems in a virtualized environment.

It would be of substantial benefit to any company employing virtualization to seek out advanced optimization technology as well.

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