iDefrag is a disk defragmentor for Mac that is in charge of optimizing the location of files in a predetermined volume.
It consists of five different defragmentation algorithms that allow you to perform the process by following different patterns. The only one of them that can defragment a mounted volume answers to the name of Quick (online).
To use the rest of the algorithms in the boot volume, it is necessary to boot the computer from a different volume. The complete version of iDefrag includes a tool to generate a booting CD/DVD with which to perform this task.
A function denominated Thermal Monitoring supervises the disk temperature at all time. If it is too high, iDefrag will stop defragmentation until the device cools off.
Comments
WARNING!!!! Do not use this utility on a late 2015 iMac with a traditional hard drive and macOS 12.6 Monterey, otherwise you will not be able to turn it off. Repeated restarts following Kernel Panic.
Ccleaner, antivirus, and now this! Isn't it supposed that Macs never need defragmentation?