FileMoveChunkSize

MyDefrag is build on top of the Microsoft defragmentation API and basically all it does is send "move this file to that location" commands to the API. The API can only move a maximum of 1 gigabyte at a time, so MyDefrag has to split up the commands into chunks.

• Do not set a very low chunk size. It will not only make MyDefrag slower (moving big chunks is far more efficient), but more importantly will cause the MFT to become bigger and will make all disk access slower (for all applications, not just MyDefrag). Files are stored in the MFT in "extends". Contiguous extends (back-to-front on the disk) form fragments. The number of extends is not listed by MyDefrag (or any other defragmentation program) but should be as low as possible, just like the number of fragments should be as low as possible. Decreasing the chunk size will increase the number of extends.
• MyDefrag has to read-only lock a file when it is defragmenting or moving that file. This can sometimes cause problems for very big files if the file is actively used (for example a database, or the Exchange mail repository). MyDefrag will release the read-lock between chunks. Lowering the chunk size will give other applications a chance to access the file.
• To make MyDefrag respond quicker to kill commands you can change the chunk size to a smaller value. Once the Microsoft defragmentation API has been instructed by MyDefrag to move a chunk it will finish moving the chunk in the background even if MyDefrag is killed, but the API will finish faster if the chunksize is lower.
• The Microsoft defragmentation API does not provide any information to MyDefrag about how far a move has progressed. MyDefrag can only update the display and the percentage counter between moving the chunks, not while a chunk is being moved. Lowering the chunksize will make the percentage counter update more often.

Syntax

Example

See also:

 Settings