Table of ContentsView in Frames

What a reallocation scan is

A reallocation scan evaluates how the blocks are laid out on disk in a LUN, file, volume, or aggregate, and rearranges them if necessary.

Data ONTAP performs the scan as a background task, so applications can rewrite blocks in the LUN, file, volume, or aggregate during the scan. Repeated layout checks during a file, LUN, or volume reallocation scan ensure that the sequential block layout is maintained during the current scan.

A reallocation scan does not necessarily rewrite every block in the LUN, file, or volume. Rather, it rewrites whatever is required to optimize the block layout.

Note: Output of a reallocation scan goes to the system log. You can view the current status by using the reallocate status command.
The following general recommendations apply to a file, volume, or aggregate reallocation scan: