2 Replies Latest reply: Feb 13, 2012 1:52 PM by legolas-woodelf
legolas-woodelf Level 1 (0 points)

I've had my iMac for about nine years and have never re-formatted/re-initialized the internal hard drive. Overall it still runs ok, though some applications do tend to freeze rather more readily than they should. I'm certain also that it runs slower than when it first came out of the box.


I've upgraded the OS a couple of times, run iDefrag a couple of times, run the sudo periodics (daily, weekly and monthly) from Terminal, cleared out caches and generally tried to look after it and keep it clean and tidy. Last week I re-installed the OS from the DVD and ran all the software upgrades to get back to 10.5.8 in an effort to fix the freezing applications issues. It's a little early to tell if this has been successful.


But generally, in googling the merits or otherwise of defragging (the whole idea still scares me), I've seen that some people recommend cloning your internal HD to an external one, initializing the internal and then cloning back, as a more elegant, less dangerous and much quicker alternative to defragging. Some people also recommend doing this perhaps annually as a routine maintenance thing. Is this worthwhile, safe or valuable and will it serve to defrag an older, somewhat scattered disk?


Surely a block level clone, by definition, won't de-frag, and anything less than a block level clone is liable to miss certain root level items resulting in a less than reliable re-build. Or have I got the wrong end of the stick completely?


I also have an external Time Machine backup, but I've read that it too can try to be a bit too clever about re-building systems and leave out certain things that it assumes are already on the drive being rebuilt. Or have I, again, got it all wrong?


The bottom line is that I don't really know what I'm talking about.


What, if anything, should I do to get my iMac back to its very best?

Is nine years a long time for a hard drive to run on the same initialization? (OK, I guess nine years is a long time for a hard drive to run at all, but given that it still seems ok [touching lots of wood] should I re-initialize it anyway in the interests of good maintenance to keep it running smooth and fast?)


My setup is:


Mac OS X (10.5.8)

17" iMac PPC G4

1.25 GHz

80 GB Internal Hard Drive with around 19 GB free.


500 GB LaCie External Drive with 6 partitions:

of which one is a clone of the internal HD,

one is the Time Machine backup,

and one is a clone of the Install DVD.


I'm sure I'm worrying too much and that my backup systems are pretty comprehensive and that the clone, reclone option would work perfectly well. But on a system this old, would it actually be beneficial (and safe) to wipe the disk and start afresh?


Any thoughts or advice most gratefully received.

Mac OS X (10.5.8), 17" iMac PPC G4 1.25 GHz 10.5.8
  • Limnos Level 8 (47,347 points)

    Realize you are running a system that postdates your Mac by several years and puts increased demand n it.  Also, you may be running software that post dates your computer by many years.


    I'd see if you can narrow down the reasons for the software freezing.


    I have a drive in my G4 that's been up and running since it was in a G3 since the late 1990s.  It ha a bad sector about 6 years ago and I wiped it with a secure erase to check blocks.  Been fine since.


    Never re-installed my OS since 2005.  Just take care of it with regular checks with Disk Utility and periodic directory rebuilds with Diskwarrior.


    Here's my archive on Fragmentation

    Apple KBase article [About disk optimization with Mac OS X|http://docs.info.apple.com/article.html?artnum=25668]


    Different views about defragmentation:


    [Optimizing Disks Is a Waste of Time|http://db.tidbits.com/article/7254]


    [Macintosh OS X Routine Maintenance|http://www.macattorney.com/ts.html#Anchor-31774]


    The links above also have links to specific tools you can use.  Here's a short list:



    Drive Genius

    DiskWarrior defragments just the Directory

    [Show Volume Fragmentation|http://www.macupdate.com/info.php/id/18451/showvolumefragmentation] (free, just shows fragmentation stats.)


    There is a difference between defragmentation and optimizing. Defragmentation results in pieces of files or free space occupying contiguous areas (puts them together so they are next to each other and "whole"). Optimizing puts things in a specific order that supposedly makes them easier to which to get access. Techtool has a defragmentation feature. idefrag also does optimizing.


    There's also two types of fragmentation; file fragmentation and free space fragmentation. You could have files that are contiguous but the free space may be broken up into tiny bits making it almost useless for file storage, or the reverse.  SpeedTools does file defragmentation but does not defragment the resulting free space.


    "Tiger automatically defragments files smaller than 20MB." This is a statement copied from somewhere but I have checked my drive and found 2MB files that were fragmented when there was sufficient contiguous space for them not to be fragmented.


    [More discussion on defragmentation|http://discussions.apple.com/thread.jspa?threadID=1826622]


    [March 2010 post by Klaus1 with extensive discussion of fragmentation|http://discussions.apple.com/message.jspa?messageID=11247504] Also read


    Extensive discussion about defragmentation, also questioning the effectiveness of cloning as a defragmentation process. - [http://discussions.apple.com/thread.jspa?threadID=1962935] Also read [http://discussions.apple.com/message.jspa?messageID=12961331#12961331] which has a case study of the effectiveness of file defragmenting and cloning.


    I think the bottom line is, unless you have pushed your drive to extremes in terms of large file creation with very little free space you probably don't have to worry about fragmentation.

  • legolas-woodelf Level 1 (0 points)

    Many thanks for the comprehensive reply Limnos, and for all the links too - interesting stuff.


    Having looked through them, on balance, I think I'm going to leave things alone for a little while.


    It also occurred to me, doesn't the Installer actually run some kind of optimizer whenever you install an OS or run a Mac Update, meaning that my disk will already have been tidied up quite a bit when I did the Install and Archive to renew my OS?


    I also ran iDefrag just to show the level of fragmentaion (see grab below). Whilst I don't fully understand what I'm looking at, I don't think it looks too bad. I'm guessing the big gap near the middle is the 10GB old system file which I deleted once Time Machine had backed it up.


    Lego Frag.jpg