Disk Defrag

M

martiansky

Registered
Does anyone defrag their mac hd on a regular basis?? I am a PC guy with a new pb 1g/1.25gb coming and defrag my PC daily...


whats the best way to go about defragin my new powerbook??
 
On Mac OS X there is no need to defragment since the OS takes care of file fragmentation for you.

Search the forum, there are lots of threads on this subject with loads of info.

PS Welcome to the greener side of the fence :cool:
 
What you need to do now, every so often, is "repair permissions" or at least "verify permissions". When you use your "Disk Utility" in "Applications" you can choose these options and watch as your computer analyzes itself and its important files. Defragging is definitely a dying need since OS X takes care of these stray bits so well. OS X even handles RAM allocation automatically! (something you used to have to set yourself on a mac, which for dyed-in-the-wool macfanatics wasn't such a bad thing...)

:)
 
RAM allocation and harddisk fragmentation haven't much to do with each other, though. But since Panther, Mac OS X is really defragmenting files on open and save if they're bigger than 20 MB. So your harddisk should not need defragmentation. Ever. (Or better: It _does_ need defragmentation and _has got_ it already.)
 
Its been said in lost of other posts- but just in case you're still enthusiastic on the defrag thing DO NOT USE NORTON, it will mess up your drive.
 
I routinely run verify/repair disk permissions and notice that there is usually a considerable amount of repair needed. Why do these permissions get corrupted at such a high rate? What part of the OS is supposed to set them in the first place and why does it get it wrong so often?

Just curious
 
fryke

I merely stated horribly that OS X has had some great advancements in the areas of RAM allocation and data storage optimization. Not having a ton of technical expertise in that area, I certainly leave any links between the two to other, more knowledgeable posters… :)

Just as long as it works, I love it! I can't believe I ever poo-pooed X in the past, being a staunch 9 "I like controlling everything" kind of graphic designer. Though I do miss coloring my folders. Yes, I know Panther has that, but it comes with tons of printing problems as well that I want resolved before I move up to it.
 
OSX provides Mac users with the old foundation of Unix. One of the benefits of Unix is its multi-user capablity. To manage the users of a system, Unix uses file ownership and permissions.
Think of Repair Disk Permissions as rebuilding the desktop in OS9 since there are tines with OSX that key file ownership and permissions are changed reason by applications, and more frequently, program installers.
When ownership and permissions get changed, things don't always work as they should. Symptoms range from programs quitting unexpectedly, preferences not being remembered, programs not launching, other kernel panics, etc.
 
My power book was severely fragged but I suppose it was because of using Photoshop so much. Since I don't have another drive in my laptop to use as a scratch disk my main drive gets really beaten up. I tried to use Norton but it failed with an error (good thing from what I read above.) I ended up using Techtool 4 even though it took 10 hours.

I'm beginning to wonder if "SuperDuper" from shirt-pocket.com might be a better solution. They say on their website that during the process of cloning a drive it automatically gets defragged. Plus it would make me feel a whole lot better knowing that I have a safety clone in case anything happens to my drive. Apparently the app will clone your whole disk, just your system, system plus Applications, plus documents or many other combinations. I wonder if getting your system into a completely installed state, making a clone for defrag, then putting the clone back cleanly would help system performance? What do you guys think?
 
On Mac OS X there is no need to defragment since the OS takes care of file fragmentation for you.
Click to expand...
Only to a very limited extent does OS X defragment files. It does this only on the boot volume when journaling is enabled and then only for smaller files which are badly fragmented (8 or more extents). It does so by copying the file to another part of the disk thus increasing disk fragmentation. If your drive is pretty full (less than 15% free space) you can benefit by running a good disk defrag utility such as Drive 10 1.1.4 or TechTool Pro 4.0.1. The benefit will be realized more in file system stability than it will in any increase in disk I/O performance.
 
I only defrag my non X partitions after i before a archive of my work. Just to clean things up a bit. And thats like... last time I did so was about December, no need now till I need to archive to another DVD.
 
kenekeu said:
I'm beginning to wonder if "SuperDuper" from shirt-pocket.com might be a better solution. They say on their website that during the process of cloning a drive it automatically gets defragged. Plus it would make me feel a whole lot better knowing that I have a safety clone in case anything happens to my drive. Apparently the app will clone your whole disk, just your system, system plus Applications, plus documents or many other combinations. I wonder if getting your system into a completely installed state, making a clone for defrag, then putting the clone back cleanly would help system performance? What do you guys think?
Click to expand...

Copying data off of a drive and then back onto the drive does indeed defrag the drive, and the reason it does is simple. When you copy data off the drive, the data is copied file-by-file. When the file is copied, it is written to the target disk in one chunk. Then it moves on to the next file, which is written as one big chunk adjacent to the previous chunk. Therefore, the copied files have no fragments -- they are on contiguous blocks on the target disk. Likewise when you copy back.

This is different from "optimization," though... optimization does indeed defragment a drive, but optimization has "profiles" which determine where the data is put on the drive depending on what kind of file it encounters. For example, back in the days of OS 7/8/9, Norton Speed Disk (the disk optimization portion of Norton Utilities) would put system files, extensions, control panels and the like at the beginning of the drive in contiguous blocks and data/miscellaneous files at the end of the drive in contiguous blocks, leaving a big, empty chunk of free space in the middle. OS X moves files around and degfragments many files on its own, and I'm a staunch believer that "optimizing" OS X does nothing beneficial, since the next time you start using your computer, OS X is moving files back around to where it likes them.

I don't think you'll see any marked improvement in performance by cloning a drive and then cloning it back, but if you'd like to try, might I suggest CarbonCopyCloner?

http://www.versiontracker.com/dyn/moreinfo/macosx/13260

It's virtually free and works wonderfully.
 
perfessor101 said:
Only to a very limited extent does OS X defragment files. It does this only on the boot volume when journaling is enabled and then only for smaller files which are badly fragmented (8 or more extents). It does so by copying the file to another part of the disk thus increasing disk fragmentation.
Click to expand...

The part about increasing disk fragmentation is not correct.. OS X defrags files when it can, and it will not defrag a file unless there's a contiguous block of free space large enough to accomodate said file in one contiguous block. It does, indeed, "defragment" that file, since the file used to be in pieces scattered throughout the disk, and after the auto-defrag, it is now in one contiguous block of space, or at least in a lesser number of fragments. OS X's auto defrag won't touch a file unless that file can be defragmented properly and to the benefit of reducing the number of fragments that file is in.
 
ElDiabloConCaca said:
OS X's auto defrag won't touch a file unless that file can be defragmented properly and to the benefit of reducing the number of fragments that file is in.
Click to expand...
There is no argument that the files are defragmented but that can contribute to additional disk fragmentation. In other words instead of all the files in one contiguous block and all the unused space in another contiguous block there are lots of small spaces on the disk to put new files.

On a drive that is getting pretty well filled up, say less than 15 to 20% free space (or even 25% if the disk is badly fragmented) that can result in a situation where there is not a large enough block of free space to write a new extents file when one is needed. Since HFS+ requires an extents file to be located in contiguous data blocks on the drive, you have just created a major job for DiskWarrior or TechTool Pro rebuilding the volume structure of the drive.
 
Ah, yes, this is what I thought you meant the first time around but wasn't sure -- yes, a close-to-full disk can produce some ugly disk fragmentation, even if the files are defragmented.

Having a disk that is close to full, though, is a bad idea I think that some people don't get. Hard disks are not static storage media anymore -- they're dynamic in the sense that they are ever-changing with general system use, and not just when you copy a new file onto it. It's a good idea to keep a good 20% to 25% of your drive free so that there is enough space to let the system move stuff around without being cramped for space. Back in the day, this meant leaving ten or twenty megabytes free, whereas today, with such large, cheap disks, this can mean leaving anywhere from 1 to 20GB free, and with hard drives already being advertised the way they are with more free space than you'll actually get, people don't want to believe that there's even MORE space on their disks they're not supposed to use.
 
Drive 10 now seems to be TechTool... Which is too expensive and does way more than disk defrag.

Isn't there something simpler/cheaper a'la the old Speed Disk?
 
You must log in or register to reply here.
Back
Top