White paper: Real-time fragmentation prevention

As I’ve written about previously, PerfectDisk has used its patented SMARTPlacement optimization strategy to prevent fragmentation for years. While organizing drives according to each individual user’s unique usage patterns, PerfectDisk also creates the largest chunk of contiguous free space possible. This free space consolidation, which has made Raxco the definitive leader in this technology, has the effect of greatly reducing the rate of fragmentation that occurs on a drive.

Solutions that simply focus on defragmenting files end up repeatedly scattering and rearranging files across the drive. With no attention to free space consolidation, free space becomes fragmented and as new files are created, there is a greater likelihood that they get created in a fragmented state.

With PerfectDisk 12, we’ve extended our support to  technology that people commonly refer to as fragmentation prevention. OptiWrite is our new file system filter that eliminates fragmentation in real time by ensuring that up to 100% of file are written to the file system in a single continuous stream. In addition to saving the resources normally required to analyze and defragment files, it ensures maximum sequential write performance for storage devices, effectively eliminating slow random write behavior. OptiWrite performs above and beyond its competition because it was designed to prevent file fragmentation in a way that does not negatively impact the performance of subsequent reads. For a detailed explanation and testing results, see our new white paper Real-time Fragmentation Prevention with OptiWrite.

As the white paper points out, fragmentation prevention is not enough — it needs to be done intelligently. The majority of the energy savings that can be attained through the prevention of fragmentation is not in the act of preventing fragments or in the avoidance of defragmentation, but in the performance gained when reading back files after the fact. Once this is understood, it becomes evident that in order to attain the best performance and energy savings, the prevention solution must factor in the placement of data and avoid the excessive creation of free space fragmentation. Otherwise the solution will simply trade one problem for another and require that additional system resources and energy costs be spent to fully restore performance. The simple act of preventing fragmentation is not enough to justify doing so if the solution sacrifices fast sequential reads for slow random reads.Free space fragmentation is the most prevalent cause for the creation of fragmentation, and failing to avoid it when preventing files from fragmenting simply delays the inevitable. If you simply prevent file fragmentation at the expense of creating free space fragmentation, a volume will inevitably be forced to fragment files regardless of any prevention method. Any solution that fails to understand this in its implementation will at best delay the need to defragment, and at worst, eventually promote the need to do so. There is an additional consideration to be made; thin provisioned systems that use high water marking are negatively impacted by any form of fragmentation prevention that creates excessive amounts of free space fragmentation. This is because such solutions artificially push files down the volume to higher LCN ranges by creating large free space gaps between files. The use of such a solution will promote the rapid provisioning of a thin provisioned volume and should be avoided. OptiWrite is designed with these considerations in mind by allowing its behavior to be customized as needed. Not all data, hardware and workloads are created equal, and so to provide the best performance and energy savings, a fragmentation prevention solution must provide sufficient flexibility and customization to meet the task at hand, including improved virtualization performance.Intelligent, real-time fragmentation prevention with OptiWrite — available only with PerfectDisk 12.





Category: PC PerformancePerfectDiskStorageVirtualization

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