What is a Disk Defragmenter?

Disk defragmenter is a system utility for analyzing local volumes and finding and repairing fragmented files and folders. The disk defragmenter command is the defrag command, which can defragment the disk from the command line.

Chinese name: Disk Defragmenter
Foreign name: Disk defragmenter
Purpose: Analyzing local volumes

Form: Scattered preservation
Nature: Data exchange
Related procedures: VoptXP, Diskeeper, defraggler

Causes of Disk Defragmenter Fragmentation

In Windows logical volumes, files are not always stored in contiguous clusters of disks, but are scattered and stored in different locations. When the physical memory required by the application is insufficient, Windows generates a swap file (usually: pagefile.sys) in the disk, and virtualizes the disk space occupied by the file into memory, that is, virtual memory. Because frequent data exchange is required in physical memory and virtual memory, the Windows virtual memory management program frequently reads and writes to the hard disk, resulting in a large number of fragments, which is the main reason for disk fragmentation. In addition, another main cause of disk fragmentation is the temporary files frequently generated by the system or application. For example, when a browser browses a web page, it needs to continuously cache, which will generate a large number of disk fragments. In addition, when installing or downloading new software, the system typically stores files on the first continuously available space that is large enough for the files. If there is not enough free space, Windows saves as many files as possible on the largest available space, then saves the remaining data on the next available space, and so on.

Disk Defragmenter Fragmentation

When the system runs a program, the head of the hard disk drive first searches for files required for the program to run, and then reads the data into memory or disk cache. The search time is called average seek time in the hard disk performance index, and the unit is millisecond (ms). If the relevant files of the application can be placed in the continuous space of the disk, the search time of the head will be greatly reduced. The same is true when reading. The time required for the hard disk to read data in the sector below the magnetic head is only one-fifth of the time required to move the head to another location and read the data. When reading the disk, the system will first check if the data is in the cache, if there is, read it directly; if not, read it from the hard disk. When you need to read the same data multiple times, the cache is very useful, but for the first time reading a file, the cache is powerless. Therefore, search time and read time greatly affect the efficiency of program execution.

According to the official Microsoft documentation: the more fragmented the volume, the lower the performance of the computer's file input / output system. We can also understand that: excessive disk fragmentation causes the head to continuously search and read data belonging to a file in different places, thereby reducing the efficiency and speed of system operation. Over time, it will also reduce the life of the hard drive.

In summary, it is necessary for us to analyze and organize the disk fragmentation regularly (for example: once a month). Disk Defragmenter can analyze local volumes and defragment and merge fragmented files and folders so that each file or folder can take up separate and continuous disk space on the volume. This allows the system to access files and folders more efficiently and save new files and folders more efficiently. By merging files and folders, Disk Defragmenter will also merge the free space on the volume to reduce the possibility of new files becoming fragmented.

Disk Defragmenter Best Practices

Prepare for Disk Defragmenter

Analyze the volume before defragmenting. After analyzing the volume, a dialog box tells you the percentage of fragmented files and folders in the volume, and whether to recommend defragmentation. Volumes should be analyzed on a regular basis and defragmented only if recommended by the disk defragmenter. Volume analysis at least once a week is a good guideline. If you don't need to defragment volumes frequently, you can do volume analysis once a month instead of weekly.

Disk Defragmenter adds files

When users add a large number of files or folders, there may be excessive fragmentation on the volume, in which case it is important to analyze the volume. In general, volumes on file servers that should be accessed frequently should be defragmented more frequently than volumes used by individual users.

Disk defragmenter ensures free space

The disk must have at least 15% free space for Disk Defragmenter to fully defragment. Disk Defragmenter uses this space as a sort area for file fragmentation. If the volume has less than 15% free space, Disk Defragmenter can only partially defrag it. To increase the free space on the volume, delete unnecessary files or move them to another disk.

Disk Defragmenter Defragment Time

Defragment the file server's volumes during low volume use to minimize the impact of the disk defragmentation process on file server performance. The time it takes for the disk defragmenter to defragment a volume depends on several factors, including the size of the volume, the number of fragmented files on the volume, and available system resources.

Disk Defragmenter Installation Software Note

Defragment a volume after installing software, upgrading, or a fresh installation of Windows. Lots of debris can form on the volume after installing the software, so run a disk defragmenter to help you get the best file system performance.