Fragmentation can be remedied by re-organizing files and free space back into contiguous areas, a process called defragmentation. File system fragmentation negatively impacts seek time in spinning storage media, which is known to hinder throughput. It is a special case of data fragmentation. In computing, file system fragmentation, sometimes called file system aging, is the tendency of a file system to lay out the contents of files non-continuously to allow in-place modification of their contents. Personally I prefer iDefrag.Visualization of fragmentation and then of defragmentation IDefrag, Drive Genius and a handful of other utilities will all defragment your hard drive as well. If done as part of a backup routine the time hit may not be terrible but it's free to do it this way. This is done using Carbon Copy Cloner or SuperDuper and requires an extra hard drive. The most popular options for defragmenting a hard drive for OS X I've used and run across are:Ĭloning the hard drive to another drive and back. For your standard user - a near non-issue. The OS itself also defrags 'small' (20MB or smaller) files on the fly since 10.3 (Panther).įragmenting still happens and you can see performance drop because of it, especially in video editing systems or a workflow that requires the ability to read or write large files quickly to the disk. Speaking for Mac OS X specifically HFS+ does a decent enough job of trying to keep things from being fragmented compared to older systems but it still happens just not on the same scale. All filesystems will fragment but newer ones are more resistant to fragmenting so badly.

Useful in certain circumstances but it's less of an issue than it was with FAT or regular HFS.

My answer on Server fault fits here as well : I suggest also taking a look at Server Fault's answers as well: Mac OS X 10.2 and later includes delayed allocation for Mac OS Xįragmentation was often caused by continually appending data to existingĪggressive read-ahead and write-behind caching means that minor Hard disk capacity is generally much greater now than a few years ago. I think the best answer for this comes straight from this apple support KB

Disk fragmentation on mac