On-line Defragmentation - A Superior Solution

An off-line defragmenter first analyzes an entire disk partition to determine the state of fragmentation and then maps out a rearrangement of the files on the disk that will reduce or eliminate the fragmentation. After mapping out where the files should go, it rearranges them. Off-line defragmentation has the following drawbacks:

1. An off-line defragmenter may rearrange all the files on the disk and make them all, or mostly, contiguous at the end of the rearrangement pass, but as soon as the disk is returned to service, it immediately begins to re-fragment. This is especially true on multi-user systems and on fairly full disks. As soon as any user extends or creates a file, the "perfect" disk is no longer perfect.
2. Having a separate analysis pass and then the file rearrangement pass has to be done off-line; that is, the disk cannot be used for any other tasks while off-line defragmentation is taking place, because if a user were to add a new file, delete a file, or extend an existing file, the analysis would instantly become invalid and mapping based on an incorrect analysis could result in catastrophic data loss. By taking the disk out of service, so no user application can access any file on the disk, this danger is eliminated. However, taking the disk out of service, obviously, means no one can use it. The disk, if not the entire system, is "down" for the duration of the defragmentation activity and the users' data is inaccessible.

Diskeeper, an on-line defragmenter, works constantly in the background, while the system is up and running. Defragmentation occurs on the fly, while users continue to work without interruption. Diskeeper uses only idle resources and will not impact your system's performance. When CPU resources are needed for other processes, Diskeeper backs off and resumes when resources are again available. Therefore, with Diskeeper running in the background, the degree of fragmentation can be kept consistently low, with no inconvenience to the users.

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