Chapter 8: Disk Space Analysis › Disk Fragmentation Investigation

Disk Fragmentation Investigation

There are three ways to read the Disk Space report to evaluate disk fragmentation. One way is to compare the size of most of the current files with the size of most available space to determine if fragmentation occurs as new files are created on the disk. Another way is to look at the number of files on a disk and the size and number of extents per file to determine if files on the disk are fragmented.

When a file being written exceeds the space allocated to it, an additional group of contiguous blocks is allocated at another location on the disk. This is called an extent. The following figure shows a file with extents. The third way is to look at the number of files with extension headers to determine if the disk is fragmented.