Boot Optimization versus File Optimization

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Optimization itself is an old concept that dates back to the OpenVMS system. During the 1980s, several software developers investigated the theory that placing files in an optimum location could reduce the amount of fragmentation. Although the idea has marketing appeal and provides a pretty pattern of file colors on visual disk representations, file optimization tends to utilize too many system resources for the minor performance benefits it can sometimes return. Why? The algorithms used in the operating system and file system act to scatter newly written or revised files throughout the disk in available pieces of free space. Thus, file optimization is sometimes working 180 degrees opposite the file system and operating system. The optimization algorithms dictate a set pattern on the disk for files that the operating system and file system algorithms ignore when data is written to or deleted from disk (see Chapter 8).

One or two vendors still advocate file optimization on Windows systems. They will dispute the statements made here regarding the value of optimization and come up with convincing arguments for the value of file placement; however, the acid test is real-world deployment, and file optimization just is not that popular in the enterprise marketplace. Those networkable defragmenters that bundle defragmentation with file optimization do not seem to do as well as those that stick to standard defragmentation.

Boot optimization, however, is a different matter. The technology is aimed at producing faster system boots on XP and does not compete for system resources. It addresses only a few files (some system files, DLLs, etc.) which are rarely modified. Prefetching to speed up access, therefore, supplemented by layout optimization does produce some small benefit. The potential gains, though, will not be fully realized unless disks are regularly defragmented.

Here is an example to illustrate why regular defragmentation must be carried out regardless of Fastboot. Consider a Word file called bio.doc. The winword.exe and related files used during boot up may have been well organized in a precise location on disk and fetched in advance to make them more quickly available, but if bio.doc is fragmented into hundreds of pieces, all the gains achieved during application launch will be lost due to the excess I/Os required to open the document.

As mentioned previously, optimization procedures can lead to overconsumption of system resources. To guard against this, Windows XP makes sure a machine has been idle for at least 30 minutes before it attempts to optimize the boot files. Accidentally touching the mouse aborts the layout optimization.



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Server Disk Management in a Windows Enviornment
Server Disk Management in a Windows Enviornment
ISBN: N/A
EAN: N/A
Year: 2003
Pages: 197

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