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Thread: Do you need to defrag your mac?

  1. #1

    Do you need to defrag your mac?

    I have been using Macs since 1983. Through the first 20 years of using Mac, I have used various programs to defragment the hard discs on Macs that I have owned. I did it with various versions of Norton Utilities, a program called Speed Disk. It was very satisfying doing defragmentation, knowing that I have a hard disc where all the files were no longer scattered in pieces all over the disc and packed solid at one end of the disc. Starting several years ago, all the programs for defragmenting the Mac seemed to have disappeared off the market.

    I forgot all about defragging until I started to use Parallels to run Windows XP on my powerbook. Windows XP seems to want to defrag every time it booted up. Unfortunately, unlike speed disk or other program, it takes a lot of time without showing you what it is doing. I often wondered how much it did and how much it helped. More important, I began to wonder about defragmentation on OSX. Here is what Apple has to say about the matter.


    http://docs.info.apple.com/article.html?artnum=25668
    Do I need to optimize?

    You probably won't need to optimize at all if you use Mac OS X. Here's why:

    * Hard disk capacity is generally much greater now than a few years ago. With more free space available, the file system doesn't need to fill up every "nook and cranny." Mac OS Extended formatting (HFS Plus) avoids reusing space from deleted files as much as possible, to avoid prematurely filling small areas of recently-freed space.

    * Mac OS X 10.2 and later includes delayed allocation for Mac OS X Extended-formatted volumes. This allows a number of small allocations to be combined into a single large allocation in one area of the disk.

    * Fragmentation was often caused by continually appending data to existing files, especially with resource forks. With faster hard drives and better caching, as well as the new application packaging format, many applications simply rewrite the entire file each time. Mac OS X 10.3 Panther can also automatically defragment such slow-growing files. This process is sometimes known as "Hot-File-Adaptive-Clustering."

    * Aggressive read-ahead and write-behind caching means that minor fragmentation has less effect on perceived system performance.


    For these reasons, there is little benefit to defragmenting.

    Note:Mac OS X systems use hundreds of thousands of small files, many of which are rarely accessed. Optimizing them can be a major effort for very little practical gain. There is also a chance that one of the files placed in the "hot band" for rapid reads during system startup might be moved during defragmentation, which would decrease performance.

    Well, it seems that they may be right. This person actually defragmented his OSX disc and compared the speed of the disk before and after. There was no significant difference.
    http://forums.mactalk.com.au/showthread.php?t=32660

  2. #2
    I'm typing this on my old G4 Powerbook (I use it for music & basic web stuff in my bedroom), still running on its original install of 10.2 from late 2002. I've never reformatted this machine or anything... it keeps on going & I'm not sure it'll die... the screen crapped out on me but that's the only thing, so it's hooked up to an old cheapo 15" LCD. The current uptime is 35 days, 23.5 hours, w/ no noticible degredation in performance. OSX is solid, and the newer versions are even better.

  3. #3
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    The above is true with all OS's.

    I think the biggest factor is how you compute. Saving and delete all the time would cause more fragmentation and whatnot.

  4. #4
    Extreme Tips: Optimization Derby
    By Andy Walker

    Defragmenting

    Fragmentation can be a serious problem on machines that are already slow... performance can suffer if the hard drive has to piece everything back together from tiny pieces scattered throughout the hard drive. How much of a difference does it make, though?

    With lightly defragmented drives, not a whole lot. If your system is really fragmented, though, it always helps to get everything together every so often. With our benchmark, we saw very little change after defragging the drives on our newer systems...a small enough change that it could well be statistical error. On the other hand, after a thorough defragmentation, our Windows 98 system booted up in half the time it previously took.

    Call For Help (RIP)
    The test of success is not what you do when you are on top. Success is how high you bounce when you hit the bottom
    --General George Patton

    Complex problems need to be solved collectively.
    ––Paul Nussbaum
    usc87.blogspot.com

  5. #5
    Well, I am now defragging my two Mac laptops. One is a Powerbook G4 with the motorola processor and a Macbook Pro with a duo core Intel. I did not do the extensive testing of application speeds, figuring that it would not do that much. I am doing the defragmentation because the discs on on both these powerbooks do not have enough free space for a Disk Warrior rebuild of the directory. Anyway, since my computers are taken up by the defragging, I thought I would take the time to post my experience.

    Disk Warrior, SuperDuper, and iDefrag

    What is Disk Warrior? It is my favorite disk utility. It rebuild the directory or catalog of disks and corrects any problems that it sees. After any unexplained crash, I rebuild the disk directory. In the last couple of month, even though I have over 45 Gb of apparent space on the disk, it said that it was unable to do a "safe" replacement in the directory, meaning that it was unable to find any space on the disk that is 100 Mb, since my disk catalog is probably about 100 Mb.

    So, I purchased the most highly recommended of the defrag programs for the Mac: iDefrag from Coriolis ($30). It has a demo version but that could only be used on disks of 100 Mb of less. It came with a Coriolis CDmaker that can make a bootable CD containing the iDefrag (or other programs from Coriolis). So, the first thing that I did was to make a bootable CD.

    Most programs make you get the CD template from your original startup disks. However, Coriolis CDmaker gves you the option of downloading the CD system template from internet. It allows you to choose a CD template for powermacs, intelmacs, or both. I chose both. The final disk was 800 Mb, more than the standard CD. But, it fitted okay on a DVD disk. You of course need a high-speed internet connection since these templates are 160-300 Mb.

    I backed up both disks to an external hard drive, using a program called Super Duper that I recommend highly. It makes a bootable copy of my disk. Subsequent backups are much faster because it replaces only what is new, taking only a few minutes. Anyway, I had not backed up my disks in some time and it took about an hour to update the files. One should never defrag a disk without a backup.

    By the way, if you have a backup drive, you should use a procedure called backup and restore to defragment your disk. All the you have to do copy your current drive onto an external drive, book up on the external drive, erase your current computer disk, and then copy your backup disk back onto the computer's disk. This is a so-called copy and restore procedure will defragment the disk.

    The time required for do this is actually quite considerable if you are doing a copy and restore from scratch. For example, if you have a 200 Gb drive and your read/write speed is 10 Mb/sec (which is reasonably fast), it will take you about 6 hours to copy 200 Gb in one direction, a total of 12 hours. In contrast, using iDefrag, I was able to defrag a 100 Gb drive in 6 hours. I expect that I will probably do so on my 200 Gb drive in about 8 hours.

    Defragging the Powerbook G4

    I booted up one of my computers (the Powerbook G4) on the DVD. The program came on line but it was not recognizing the hard disk. At first, I thought that something was wrong with the disk. However, about 15 minutes later, it did. I guess that program not only had to recognize the hard disk but must have been reading the catalog and directory of the disk, getting it prepared for display. Patience is needed.

    There are five modes of defragmentation: compact, metadata, optimize, quick (online), full defrag. I chose the optimize optimize and it took about 6 hours to defrag abougt 100 Gb. The disk did not seem badly fragmented (i.e. 1% of the files) but the color map suggested that over 50% of the disk is red, the color indicating fragmentation.

    The term percent defragmentation is misleading. Having 1% fragmentation may seem to be reasonable but it can be quite a lot. For example, is I have 655,569 files on the the disk, 1% fragmentation means that I have over 6000 fragmented files. More important, my free space was fragmented into many thousands of pieces and I had very few space for big files. Remarkably, after defragmentation in the optimize mode, I still had free space fragmented into 34 pieces and my catalog file of 65 Mb was in 4 pieces. So, I am doing a full defragmentation of the disk.

    Defragging my MacBook Pro

    In the meantime, after having backed up my Macbook Pro drive onto an external drive with Super Duper and having had a successful defragmentation experience on the my old Powerbook G4, I screwed up the courage to go ahead to defrag by Macbook Pro. I booted up the computer on the external hard drive and used iDefrag on the computer's hard disk.

    Because I don't want to be without the use of my computer for 8 hours (the previous computer disk of 100 Gb took 6 hours), I chose the Quick Online mode of defragmentation. While it may be quicker, it is not as quick as I had hoped. It is now nearly an hour later and the progress bar is only 15% or so. So, I suspect that it will 6 hours or longer. Incidentally, I am able to use my computer (booted on the external hard drive) while this is going on... that is how I am able to post here.

    Defragmentation causes almost continuous activity of your disk. iDefrag monitors the temperature of the disk and did so on the Powerbook G4. However, it gave a message saying that it was unable to monitor the temperature of the Macbook Pro. So, I am using a program called iStat to monitor the temperature of the computer. There is no question that the computer is hot and both of its fans are running. My CPU A is at 75 degrees C. My memory banks are at 57 degrees. My enclosure bottom is 36 degrees.

    So far so good. It is about a quarter of the way through the Quick Online Defrag and it has been about an hour. I will report later.

    Wise.

  6. #6
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    Quote Originally Posted by PN
    Extreme Tips: Optimization Derby
    By Andy Walker

    Defragmenting

    Fragmentation can be a serious problem on machines that are already slow... performance can suffer if the hard drive has to piece everything back together from tiny pieces scattered throughout the hard drive. How much of a difference does it make, though?

    With lightly defragmented drives, not a whole lot. If your system is really fragmented, though, it always helps to get everything together every so often. With our benchmark, we saw very little change after defragging the drives on our newer systems...a small enough change that it could well be statistical error. On the other hand, after a thorough defragmentation, our Windows 98 system booted up in half the time it previously took.

    Call For Help (RIP)
    Paul, A phenoix has risen Lab with Leo

    It's now done out of Vancover. Everyone but Mike and Amber/Cali

  7. #7
    Ok, I'll have to review this thread more thoroughly later. Haven't defragged my iMac since getting it this past December.

    I was curious about deleting cache and other auto saved stuff. I have much of it (eg. on 3 browsers, etc.) not to auto delete, so I can manually get rid of them, and secure delete. Wondering if this matters much, and /or if there is a better more efficient way to secure delete all the cache and dwnlded stuff. The mac is unlike the windows, which saves almost everything in many different directories or folders sometimes. With windows, I used to over-write my deleted stuff, when freeing up space (tho I know there's some debate on doing some of this, eg. w/window washer etc.)

    With MAIL also, I'm also not just trashing and deleting.

    So, anyway, thus far, I'm just secure deleting what I put into trash. I began using the OnyX, but not sure what real benefit this has been, so haven't used much.

    Feedback on this, pleeeeeaase. Thanks!

  8. #8
    interesting. thanks for investigating, wise

  9. #9
    Quote Originally Posted by chick
    Ok, I'll have to review this thread more thoroughly later. Haven't defragged my iMac since getting it this past December.

    I was curious about deleting cache and other auto saved stuff. I have much of it (eg. on 3 browsers, etc.) not to auto delete, so I can manually get rid of them, and secure delete. Wondering if this matters much, and /or if there is a better more efficient way to secure delete all the cache and dwnlded stuff. The mac is unlike the windows, which saves almost everything in many different directories or folders sometimes. With windows, I used to over-write my deleted stuff, when freeing up space (tho I know there's some debate on doing some of this, eg. w/window washer etc.)

    With MAIL also, I'm also not just trashing and deleting.

    So, anyway, thus far, I'm just secure deleting what I put into trash. I began using the OnyX, but not sure what real benefit this has been, so haven't used much.

    Feedback on this, pleeeeeaase. Thanks!
    Chick,

    I strongly recommend two programs (Super Duper and Disk Warrior) and the purchase of an external hard disk (i.e. Source) for backup. The combination of the drive and the the two programs will cost you about $330 but, in my opinion, is very well worth every dollar.

    An external hard disk is the fastest, most convenient, and best way of backing up your computer's hard disk. For example, you can buy a 500 Gb external hard drive for $170 or less (Source).

    Superduper is by far the best disk backup program for the Mac (Source). You can download it and use it for free, pay the $27.95 later if you think that it is good.

    Disk Warrior 4 is the best disk utility program, period. It fixes your disk in ways that no other single program can. It does it incredibly quickly. It is reliable and never fails. http://www.alsoft.com/DiskWarrior/ It unfortunately costs $100 but you know that when they charge this much and it is one of the most popular mac programs, it is worth it.

    Regarding deleting caches and other autosaved stuff, that is only if you are really hard up for disc space. It doesn't slow you down. I would leave it alone until you really need the space. Onyx does *not* get you out of trouble and might get you into trouble if you don't know what you are doing. There are some people who advocate a program called Drive Genius but I don't have any experience with it (Source). I have bought Micromat Techtool Pro but rarely ever use even though it has many more features. I like Super Duper and Disk Warrior because they do the job and doesn't have any fluff. Finally, why are you doing secure deletes? Are you worried about FBI looking for child pormography on your computer? If not, leave it alone. It does not free up any disk space.

    Okay, now let me continue with my comments on iDeFrag before I forget. I have now finished defragging both of my laptops hard drives (PowerBook G4 100 Gb and MacBook Pro 200 Gb). It took about 12 hours total to do both sequentially. I started the "optimized defrag" on the G4 100Gb at 3 AM, went to sleep, got up at 8 am and it was done. I then did a Super Duper back up of my MacBook Pro and did a "Quick Online" defrag. That finished around noon-time. In the meantime, I did a "Full Defrag" on the G4 100Gb and that took about 3 hours. I have been using the G4 for the last 2 hours and it seems faster. I am planning to do a "metadata defrag" next on the MacBook Pro. There has not been any glitches and crashes. I think that it is a safe and reliable program that does what it is supposed to do. Finally, I want to say that it is very important that you defrag only disks that have been fully backed up and repaired (with Disk Warrier).

    There have been several positive reviews that confirm my positive impression:
    http://paulstamatiou.com/2006/01/05/...frag-for-os-x/. Regarding whether one should defrag or not, whether it is worthwhile, I have not yet decided. I don't think that it improves the speed of the applications by all that much. What I hope is that is will improve the reliability of the disk. If so, that would be well worth the time and money.

    Wise.
    Last edited by Wise Young; 07-17-2007 at 03:13 PM.

  10. #10
    Quote Originally Posted by Patonb
    Paul, A phenoix has risen

    It's now done out of Vancover. Everyone but Mike and Amber/Cali
    Brent, thanks. I called Cox cable this morning and requested that they air The Lab with Leo. Now we just need about a million more Yankees to follow suit.
    The test of success is not what you do when you are on top. Success is how high you bounce when you hit the bottom
    --General George Patton

    Complex problems need to be solved collectively.
    ––Paul Nussbaum
    usc87.blogspot.com

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