I think it can be, but with qualifications.
Like disk partitioning, disk defragmenting is a topic of heated controversy. Some folks swear it speeds things up significantly. Others, including the official policy from Apple for OS X, dismiss it as unnecessary—basically a somewhat risky waste of time for most users.
Apple used to have a fairly lengthy Knowledge Base article on Disk optimization and fragmentation with Mac OS X on their support site, but have replaced it with a very short one that reads, in its entirety:
You don’t need to defragment or optimize your disk when you use Mac OS X. When writing files, Mac OS X optimizes your disk space and avoids fragmenting large files into smaller segments.
If your hard disk seems to be slower than it used to be, you may need to repair your disk.
So sayeth Apple.
There are indeed reasons to be hesitant about defragmenting, especially in the absence of any evident disk related slowdowns or other problems.
On a desktop machine, if a failure occurs during optimization, such as power loss, files could become damaged and need to be restored from a backup copy.
OS X systems use hundreds of thousands of small files, many of which are rarely accessed, so optimizing them can be a major effort for very little practical gain. According to Apple, there is also a chance that one of the files placed in the “hot band” for rapid reads during system startup might be moved during defragmentation, which would decrease performance.
Also, OS X itself, especially recent versions, seems to do a pretty good job of disk management. I used to defrag my hard drives occasionally, and in some instances enjoyed a significant speed up in performance, but I haven’t bothered doing so for several years now, and don’t perceive any negative consequences.
On the other hand, if your disk(s) is/are almost full, and you often modify or create large files (such as editing video….), there’s a chance that file fragmentation could be a factor, in which case you might benefit from defragmentation, which can be performed with several third-party disk utilities. HFS+ is very good at keeping small to medium sized files from getting fragmented, but reportedly less efficient at keeping large files or free space from fragmenting, which is of particular interest to Mac-users because the virtual memory swapfile must be contiguous on the disk, so you can actually run out of virtual memory long before you run out of disk space if your free space is fragmented
If you do decide to defrag, as always with a major (and in this case somewhat risky of data loss) operation, make sure your data is securely backed-up before proceeding.
And if you want to proceed, Stellar Data Recovery has launched Stellar Drive Defrag, the Free Edition of its advanced drive defragmenting software to optimize Mac hard drives and volumes. The software is claimed to be efficient in defragmenting large files, including all associated metadata and performs full defragmentation of the entire volume or drive.
Stellar Drive Defrag supports OS X Mountain Lion 10.8 as well legacy Mac Operating Systems like Tiger, Leopard and others.
“Stellar Drive Defrag is quicker, advanced and a risk free solution for fragmented Mac volume. It’s effective and carefree defragmenting approach gives required optimization facilities and speeds up your Mac,” says Mr. Sunil Chandna, CEO, Stellar Data Recovery.
This Free Edition is capable of optimizing free space in a hard drive into contiguous memory space. Temperature fluctuations during defragmentation can be monitored and the tool is also equipped with a “color legend” that allows color customization for memory blocks under similar categories. In order to defragment the boot volume, the application offers to make a bootable DVD. You can boot the Mac system from this bootable DVD and can perform all the defragmentation operations directly on the boot volume.
A full, paid version of Stellar Drive Defrag is also available, featuring Quick, Metadata and Full defrag of Mac drives.
Features of the free Stellar Drive Defrag edition:
- Free Space Optimization
- Uses an efficient algorithm to examine portions of free space available on your hard drive and keep them at a single place to avoid fragmentation. This would in fact reduce the disk head movement and lead to a significant increase of your performance.
- Color Legend for Free Space & Selected
- The software enables applying similar color scheme to memory blocks under similar category during the process. You can change the color scheme as per your suitability that would help to plan defragment of your Mac hard drive better.
Product [Stellar Drive Defrag]