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OS X does automatic defragmenting, right?

D

doxavita

macrumors 6502a
Original poster
Jul 6, 2010
614
3
I would like to know if OS X does the defragmentation process automatically.

I transferred thousands of small files from an external hard drive to my MacBook Pro (about 16GB and 27000 small files (chess databases)). And I was wondering if doing so would slow down the system due to fragmentation. But if the defrag process was automatic then I guess there's nothing to worry about.
 
Even if it didn't basically take care of defragmentation why would transferring these small files worry you?

They are small enough that would likely not ever be fragmented, even if you re-saved them. Otherwise, they would never end up being fragmented through normal reading.

...and since it sounds like they were all copied at once, they probably ended up generally in the same area of your disc.

Now, if you saved 16GB of video, edited and deleted about half of that, imported 32Gb more, edited and then deleted 24Gb of that...etc. Then, I might worry. :)
 
mstrze said:
Even if it didn't basically take care of defragmentation why would transferring these small files worry you?

They are small enough that would likely not ever be fragmented, even if you re-saved them. Otherwise, they would never end up being fragmented through normal reading.

...and since it sounds like they were all copied at once, they probably ended up generally in the same area of your disc.

Now, if you saved 16GB of video, edited and deleted about half of that, imported 32Gb more, edited and then deleted 24Gb of that...etc. Then, I might worry. :)
Click to expand...

I see what you mean. Yes, it was a one time transfer only. I was just worried about maybe too much read/write cycles, or the MBP's hard drive wearing down because of the transfer, and the sheer amount of files, I don't know...
 
Defragmentation software comparison?

MacDawg said:
Here is Apple's support document on this issue
Disk Optimization
Click to expand...
Surprisingly the document doesn't tell that HFS+'s automatic defragmentation works only with files smaller than 20 MB in size and when the file is in fewer than 8 pieces.

It would be time for Apple to release new version of these specs and this filesystem from 1998.

I guess that I have hundreds of these kind of files in my every hdd and I have really noticed slowing in my mbp.

Has anybody seen any comparison between the most known defragmentation software for OsX?
Anything missing from the list: iDefrag, Stellar, TechtoolPro, DiscWarrior, DriveGenius, SpeedTools, DiskToolsPro?
 
Last edited:
toke lahti said:
...

Has anybody seen any comparison between the most known defragmentation software for OsX?
Anything missing from the list: iDefrag, Stellar, TechtoolPro, DiscWarrior, DriveGenius, SpeedTools, DiskToolsPro?
Click to expand...
OK. If you have money that you do not need, then give it to the poor or donate it to your favorite art museum. That will do much more good than purchasing defragmentation software.

All hard drives fragment files. It is the most efficient way to store files on a drive that is in use. Fragmentation developed a bad reputation on DOS/Windows because FATxx is a terrible file system. FATxx fragment pointers lose track of their file fragments resulting in orphaned clusters.

I have been a Mac user for more than 22 years starting with System 6.0.3. I have benchmarked my hard drive before and after defragging and optimizing. I have defragged Macs that had not been defragged after years of use. Never have I seen a measurable performance boost as a result of it. Windows/FAT32 is a different matter altogether. The performance improvement due to defragging a FAT32 drive is clear and substantial.

The takeaway message is that defragging is a Windows solution to a Windows problem. On the Mac, it is at best a waste of time and money. Apple tells you that it will do more harm than good.
 
MisterMe said:
I have been a Mac user for more than 22 years starting with System 6.0.3. I have benchmarked my hard drive before and after defragging and optimizing. I have defragged Macs that had not been defragged after years of use.
Click to expand...
You maybe don't have many big files on a full disk, but do you really think that if you don't need defragmenting, others don't need it either?
 
toke lahti said:
You maybe don't have many big files on a full disk, but do you really think that if you don't need defragmenting, others don't need it either?
Click to expand...
Oh please:rolleyes: If your hard drive is full, then you have a well-known problem that has nothing to do with fragmentation. Mac's UNIX virtual memory system requires 10%-15% of its hard drive capacity available as free space. This provides the headroom for the VM system to work properly. If your VM system does not have enough headroom, then performance will suffer.

If you are running low on hard drive free space, then an external drive [or larger internal drive] is a much better buy than defragmentation software.
 
MisterMe said:
You clearly need more storage capacity now, don't you?
Click to expand...
If I could put all my hdd's 90% full with defragmenting them few times a year and still maintain their ability to stream multiple video streams to FCP, I would save a lot of money by not having to leave those hdd's 20-40% empty.

I guess the problem comes when you're making videos, lots of cache files, previews & intermedia files are created and even after you have deleted some of them, they still leave hdd fragmented.
 
toke lahti said:
If I could put all my hdd's 90% full with defragmenting them few times a year and still maintain their ability to stream multiple video streams to FCP, I would save a lot of money by not having to leave those hdd's 20-40% empty.

I guess the problem comes when you're making videos, lots of cache files, previews & intermedia files are created and even after you have deleted some of them, they still leave hdd fragmented.
Click to expand...
Huh? File fragmentation on the Mac has never been an issue. You will read other posts on this forum that agree with my own experience in this regard. Defragmenting an HFS/HFS+ hard drive has no significant bearing on system performance. File fragmentation affects Windows, particularly FAT32, because FAT32 sucks as file system.

Windows includes a defragmentation utility because the defragmentation utility is needed. MacOS X does not include a defragmentation utility because a file defragmentation utility is not needed.
 
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