Well, almost but not quite. OS X auto-defrags all files 20MB and smaller, on-the-fly whenever the file needs it.
Many small and highly used files are moved to a "hot zone" for faster access, this hot zone would be destroyed by a whole disk defrag.
Files much larger than 20MB don't usually need defragging as the number of head repositions compared to the size of the file is low enough that the drive cache hides the issue.
The necessary exceptions are if you fill a drive more than 80% or so, then you can't defrag meaningfully anyhow, 'cause if you did defrag it would only take a day or two of use for all that work and wait time to be rendered useless. Or if you have some ultra important HUGE file size high disk bandwith requirements, like real-time editing of playing video, but then you are buying an Xsan RAID and connecting via fiber and not worried about bandwidth 'cause you have plenty.
2 words as to why you don't need to defrag an HFS+ file system: Journaled filesystem
One thing I love about my transition to Mac is the .app programs that I can just drag and drop to back up, a re-install for OSX, and restoring my apps takes about an hour (osx server edition reinstall that is, less junk i.e. iLife, office trial). Format is the best way to clean any drive
Apple Computer which knows more about MacOS X and the hard drives which support it than anyone on this forum recommends against attempts to defrag MacOS X hard drives. It makes an exception for users of files larger than 20 MB. But, the point is that for the vast majority of Mac users, defragging the hard drive is more than just a waste of time. It is counter productive.
Optimizing/defragging is best thought of as a bug work around for early Windows systems. I remember trying to maintain a late 90s Windows NT system at work, and that sucker was always heavily fragmented, with Norton Utilities blaring red alerts to defrag the system or else! Very lame.
OS X has all the defragging it needs built in. It's open source, so what do you expect? If a Unix system needed a separate defragger/optimizer, then somebody would have written one by now, don't you think?
Watch out for iDefrag, it is snake oil. Yes it preserves the "hot zone," but you how else you can preserve the hot zone? Don't run a defrag utility on your poor OS X drive.
Hi, Ive had my new mac now for a few months and was wondering if theres a defragment disk program availalbe for mac.
my second question is do macs even need to be defraged?
thanks
If I recall right Disk Warrior does this also.
Quote:
Originally Posted by Mr. Me
Apple Computer which knows more about MacOS X and the hard drives which support it than anyone on this forum recommends against attempts to defrag MacOS X hard drives. It makes an exception for users of files larger than 20 MB. But, the point is that for the vast majority of Mac users, defragging the hard drive is more than just a waste of time. It is counter productive.
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
Isn't a file over 20 MB self explanatory? In any folder, a file over 20 MB will not be defragmented because there's no real benefit to it.
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Disk Warrior does not defrag hard drives. This utility repairs directories which is used primarily to recover lost data in the event of a hard drive problem. Apple says this About disk optimization with MacOS X.
Quote:
Originally Posted by Artanis
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
A file is not the same as a folder. Files contain data or applications. Folders (directories) are logical, not physical constructs, which are used to organize your files.
Comments
OS X does this in the background automatically everytime you save a file, so it's never an issue.
Many small and highly used files are moved to a "hot zone" for faster access, this hot zone would be destroyed by a whole disk defrag.
Files much larger than 20MB don't usually need defragging as the number of head repositions compared to the size of the file is low enough that the drive cache hides the issue.
The necessary exceptions are if you fill a drive more than 80% or so, then you can't defrag meaningfully anyhow, 'cause if you did defrag it would only take a day or two of use for all that work and wait time to be rendered useless. Or if you have some ultra important HUGE file size high disk bandwith requirements, like real-time editing of playing video, but then you are buying an Xsan RAID and connecting via fiber and not worried about bandwidth 'cause you have plenty.
One thing I love about my transition to Mac is the .app programs that I can just drag and drop to back up, a re-install for OSX, and restoring my apps takes about an hour (osx server edition reinstall that is, less junk i.e. iLife, office trial). Format is the best way to clean any drive
2 words as to why you don't need to defrag an HFS+ file system: Journaled file system
Not only is that three words, but it's also completely unrelated. Journaling has to do with data integrity, not with optimal coherence.
Not only is that three words
Not any more!
Data ingerity, good point. What I was stressing was drive health rather than data health, so yes I can now see a point to defrag software. 8)
Thanks
OS X has all the defragging it needs built in. It's open source, so what do you expect? If a Unix system needed a separate defragger/optimizer, then somebody would have written one by now, don't you think?
Watch out for iDefrag, it is snake oil. Yes it preserves the "hot zone," but you how else you can preserve the hot zone? Don't run a defrag utility on your poor OS X drive.
Hi, Ive had my new mac now for a few months and was wondering if theres a defragment disk program availalbe for mac.
my second question is do macs even need to be defraged?
thanks
If I recall right Disk Warrior does this also.
Apple Computer which knows more about MacOS X and the hard drives which support it than anyone on this forum recommends against attempts to defrag MacOS X hard drives. It makes an exception for users of files larger than 20 MB. But, the point is that for the vast majority of Mac users, defragging the hard drive is more than just a waste of time. It is counter productive.
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
If I recall right Disk Warrior does this also.
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
Isn't a file over 20 MB self explanatory? In any folder, a file over 20 MB will not be defragmented because there's no real benefit to it.
....
Mr. Me what you state here is very interesting for me. I personally agree, but could you post a link to the apple website or to an apple source where it states these things? because the guy who comes at our firm to repair some old Macs runs defragment with Disk Warrior.
Disk Warrior does not defrag hard drives. This utility repairs directories which is used primarily to recover lost data in the event of a hard drive problem. Apple says this About disk optimization with MacOS X.
Also, I want to ask you what do you mean by "users of files larger than 20MB"? Do you refer to the home folder or to what folder exactly?
A file is not the same as a folder. Files contain data or applications. Folders (directories) are logical, not physical constructs, which are used to organize your files.