Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Is there a defragmenter in OS X?
- Thread starter SRLMJ23
- Start date
- Sort by reaction score
Apparently no need for one.
http://support.apple.com/kb/ht1375
A more recent link http://speedup-mac.blogspot.com/2011/08/do-we-need-to-defrag-mac-lion-hard.html
http://support.apple.com/kb/ht1375
A more recent link http://speedup-mac.blogspot.com/2011/08/do-we-need-to-defrag-mac-lion-hard.html
You don't need to defrag on Mac OS X, except possibly when partitioning a drive.
About disk optimization with Mac OS X
Five Mac maintenance myths
About disk optimization with Mac OS X
Five Mac maintenance myths
NO! Most modern file systems eliminated the need for defragmenting more than 10 years ago. This is true even for NTFS and is a testament to how bad PC admins are that they *still* perform defragmenting in this day and age.
Furthermore, defragmenting will reduce the life time of solid-state drives (SSDs), so now not only is defragmenting useless but also harmful.
Furthermore, defragmenting will reduce the life time of solid-state drives (SSDs), so now not only is defragmenting useless but also harmful.
Wrong. Defragmenting moves the files around to the correct spot on the HDD or SSD, thus increasing the life of the hard drive. Defragmentation also speeds up your computer because the hard drive doesn't need to search those fragmented files. I have a Windows PC and I defragment once a week to ensure all my files are properly placed and my computer is top-noch. Mac users don't need to worry.
Increase the life of HDD and SDD? Can you reference a reputable source? I think that's wrong.
You're the one who's wrong. First, defragmenting doesn't move files around to the "correct spot" on the HDD or SSD. There's no such thing as the "correct spot". You should learn what defragmenting is and how it works before you claim someone is wrong. jw2002 is right that defragmenting is not recommended for SSDs.
That article is about Windows, not Mac OSX. It also says nothing about SSDs. What applies to Windows doesn't necessarily apply to Mac OS X.
You've pretty much made it clear that you don't know what an SSD is. Being a solid state, there are o moving parts. By definition, ANY spot on an SSD is the "correct spot."
At the same time, SSDs have a lengthy, but still finite, lifespan based on numbers of read/writes. They mitigate this (and last longer) through the use of wear-leveling logic:
http://en.wikipedia.org/wiki/Wear_leveling
If you try to defrag an SSD, not only are you fighting against the drive's own built in protection systems, but you're subjecting it to the very thing that will hasten its failure.
And this is why defragmenting is bad, mmmkay?
Last edited:
I thought the thread was about defragmenting, not SSDs. Defragmenting is a technique used to address the delay caused when a mechanical disk head accesses a particular part of a hard disk platter. This improves performance for standard hard disks, at least in my experience.
SSDs are non-linear and don't access data that way. I don't think a defragmenter designed for a standard hard disk would have much effect on an SSD except to wear it out. As SSDs are made out of flash memory that wears out, I wouldn't defragment one, or buy one, at least the present generation. A standard hard disk at least gives you some warning that it is going to fail. A flash memory device can one day fail all at once. Eventually flash memory SSDs will be replaced by SSDs made out of standard ram with little built in batteries and they will be faster and not wear out, at least not as quickly. But thats another topic.
I suspect that the reason Apple insists that defragmentation is unnecessary for standard hard drives is that if you actually sit down with something like Idefrag and try to defragment a reasonably-sized (500gb) hard disk that is about half-full of of stuff like the Imovie, Photoshop, and Garageband files my girlfriend's machine is full of, it takes forever - like it would have to be running idefrag something like 24 hours in special offline mode during which time you couldn't use the machine for anything else!! Idefrag seems to put all of the system and application files at the front of the drive, which I suppose makes some sense for a mechanical hard drive, although I would prefer that it did that only for the most used apps. After some defragmentation, the hard disk makes less noise which means there is less repetitive disk access, though I don't know how much faster the machine really is.
SSDs are non-linear and don't access data that way. I don't think a defragmenter designed for a standard hard disk would have much effect on an SSD except to wear it out. As SSDs are made out of flash memory that wears out, I wouldn't defragment one, or buy one, at least the present generation. A standard hard disk at least gives you some warning that it is going to fail. A flash memory device can one day fail all at once. Eventually flash memory SSDs will be replaced by SSDs made out of standard ram with little built in batteries and they will be faster and not wear out, at least not as quickly. But thats another topic.
I suspect that the reason Apple insists that defragmentation is unnecessary for standard hard drives is that if you actually sit down with something like Idefrag and try to defragment a reasonably-sized (500gb) hard disk that is about half-full of of stuff like the Imovie, Photoshop, and Garageband files my girlfriend's machine is full of, it takes forever - like it would have to be running idefrag something like 24 hours in special offline mode during which time you couldn't use the machine for anything else!! Idefrag seems to put all of the system and application files at the front of the drive, which I suppose makes some sense for a mechanical hard drive, although I would prefer that it did that only for the most used apps. After some defragmentation, the hard disk makes less noise which means there is less repetitive disk access, though I don't know how much faster the machine really is.