MisterMe said:
People who claim performance increases as a result of MacOS X hard disk defragmentation are either trying to fool themselves or everyone else.
.....
I'll try not to take that as a flame. It's hard, though.
Again, you're generalizing. I don't doubt that your personal experience has not shown defragmenting to help, but that hardly means that it never does for anyone. On the other hand, my personal experience quite clearly proves that it can be an issue. So yes, I am a big proponent of defragmenting, in a way. But I don't blindly recommend it. Note that whenever I speak of defragmenting, I always mention that it's not the answer for everyone, and give people tips on how to know if it's right for them. I think this is more helpful than saying it's not a problem simply because it's never been a problem for
you.
On this forum, Mikuro is strong proponent of defragging his Mac. This is despite the fact that Apple has explained in quite good detail that the physical and logical memory maps of MacOS X hard drives are not the same. Since Apple keeps the physical map private, hard drive optimization software will actually work at cross purposes to the user's intent.
I've read a lot of what Apple says on this, and none if it applies to everyone. But I've honestly never heard this map business before. It sounds like you're talking about memory, not disk space. Care to link?
Aside from that, I've never recommended any defragmenting software. I don't trust any of it. As I've mentioned several times, I take care of it simply by backing up, reinitializing and restoring.
In any case, you can spout all the theory you want, but it doesn't change the facts. If you think I'm lying about my experience, though, then there's really nothing I can say to convince you.
That said, I am willing to look at verifiable hard numbers. Absent hard numbers to the contrary, I remain convinced that defragging your MacOS X hard drive is a waste of money and time.
I admit, I've never compiled numbers on it. I never needed to. The obvious effects before and after are enough for me.
Before: Insane disk thrashing accompanying any disk activity. Slow movie playback. Slow file copying. All slowness accompanied by abnormal disk noise.
After: A happy-sounding disk. Good playback performance, even at very high bitrates. Fast copying.
I'm actually about to defragment one of my partitions, as I mentioned before. I will benchmark movie playback and file copying for you before and after, and I'll post the results. Are there any particular tests you'd like me to run as well?
There is no way for an OS to avoid fragmentation without hurting performance even more than fragmentation would. There's just no way. OS X does a fine job trying much better than other OSes but there are limits to what it can do, and there are limits even to what it
tries to do. It's not perfect. It's not magical. I don't know why so many people insist that it is.
That said, again, I
agree that it's good enough for most people. I've never said otherwise. But "most people" is not everyone. So for the non-most-people out there, I think it's worth presenting the other side.
I nondestructively converted my HFS drive to HFS+ regaining about 40% of my nominal storage capacity in the process. The conversion left my memory map looking like confetti with several damaged files. TechTools Pro returned my memory map the lovely rainbow that we love so well. Still even this change from most unoptimized to most optimized hard drive yielded no significant performance boost.
Actually, there's no reason to expect such a thing to yield a performance boost, because the conversion didn't fragment any files it just created new fragments of free space. So your performance would stay exactly the same as before. If you filled that free space, then it might have become a problem (depending greatly on HOW you filled the space).
...but if one doesn't work with large video files (I'm assuming you're referring to home videos, movies, etc., which I don't do) and basically just use my computer for Internet and writing and the occasional photo, then I probably don't have to worry about defragging and can just stick to the basic maintenance of cron scripts, permissions repairs and cache cleaning. Right?