defrag hard drive

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so i just read the information on Drive Genius 3
i know its a sales ad
but in all seriousness
how important is it to defrag your Mac hard drive?
im just curious
 

vansmith

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Not that important. Apple themselves suggest that there is a lot of work that goes into defragging a drive that produces little benefit.

Although it's an old article, you might want to read this.
 
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good read, thanks for the info
 

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About the only times I have bothered with this is if I am moving/removing a lot of large audio or video files. I have also had to use this when setting up a Bootcamp partition. The Bootcamp Assistant wants continuous space.
 
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so i just read the information on Drive Genius 3
i know its a sales ad - but in all seriousness - how important is it to defrag your Mac hard drive? - im just curious

Hi - last spring, wife & I switched over to Apple (in my retirement) - had been on PCs for decades, and defragging HDs was as common as using toilet paper - ;)

About a year ago I re-opened an old thread here on the topic - check the second page of this THREAD - might answer a few of your questions?

As for myself, my MBPro has a SSD which should NOT be defragged - our iMac has a 1 TB fusion drive (128 GB SSD portion), so no plan to touch that either. Good luck - Dave :)
 

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The truth is all spinning platter type hard drives will fragment over time - including those used with OS X. Microsoft for many years stated that the NTFS file system was immune to fragmentation, however, it was later proven that it fragmented almost as much as that of FAT, FAT-32. HFS+ is NOT immune to fragmentation regardless of what Apple is touting. HFS+ does do a better job of preventing fragmentation but over time as the drive fills up, it will fragment slowing things down.

I can't speak for Drive Genius, but I use a program called "iDefrag" which has proven to be very effective at removing fragmentation and consolidating free space.
 

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I've used then defray function in Drive Genius the few times I have needed to do this. Never used iDefrag so can't compare the two programs. Drive Genius seems to do pretty good job. I've run it a few times with no issues.

When using either of these programs, or any program that defrays the drive, make sure you have a backup just in case something goes wrong. If you are running a notebook make sure that you are using electrical power. If your battery goes down during a defray your drive can be unusable until you format the drive and copy the data back. Not common but possible.
 

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Also... it's better to do the defrag procedure overnight as it can take hours to complete. And best to run the defrag program from bootable media not your hard drive, although it is possible.
 
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Hi Guys - thanks for the great information and advice on defragmentation of HDs - now, our OP has not specified which type of drive is in question (unless I missed it?).

So, just for clarification for those coming new to this thread, there are three drive options: 1) Mechanical HD; 2) Fusion Drive (SSD + mainly moving HD); and 3) SSD. From my understanding, the SSD drives should not be defragmented & the Fusion Drives probably not?

Now as to a mechanical HD formatted w/ Mac OS Extended (Journaled), how often should these be defragmented, and what might be the criteria for making that decision? Thanks for further comments - Dave :)
 

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SSDs and Fusion drives should never be de-fragmented as that could prematurely wear them out. As for when a spinning hard drive should be de-fragmented, my guess would be when it's using 50% or more of its capacity. Although I've run iDefrag on a drive that was only around 20% filled and experienced an improvement in boot times.
 

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When to defrag OS X?

That all depends on how picky your are about the speed of your machine and whether you notice your machine slowing down or not. A lot of folks do not even notice it.

For those that simply use their machines for email, the web, a couple of cheesy non-3D games and never fill up their drive over 30-40% used space - and don't really notice much, if any, slow down - those that just used Windows and never, or rarely, did any maintenance on their Windows machines - probably never. My wife used her first Mac for 6 years, went from 10.4 with in place upgrades to 10.7 and the only maintenance done on her machine in all that time was to run Onyx once every 6-12 months.

For those that notice a half second slow down in app launch times or a 10 second increase in boot times - don't like it and Onyx doesn't take care of it - the ex-Windows overclockers, hard core gamers, those that spent 3-4 hours a week cleaning and defragging their Windows machines 'before' it slowed down - re-installing Windows every 6 months because that was the only way to really clear all the junk out of the registry and get your speed back - you install and uninstall 50-100 apps a year just testing and playing around with stuff, you move a few hundred GBs of movies or other data on and off the drive - personally, I do all the above - or, you just want your machine running as fast as possible - all that crowd likely will want to defrag.

After setting up a brand new drive &/or just a wipe and clean install of OS X - then installing all of your regular apps or a restore from Time Machine - in all my testing, iDefrag has consistently decreased the boot time in that scenario by 10-15% minimum. I maintained consistent boot times of 26-28 seconds with 10.4-10.7 on an '06 MBP.

Personally, I believe everyone that uses their computer can benefit from an occasional defrag.
How often and whether the entry price of $30 (was $40 when I bought the first version) for iDefrag is worth it - that's up to how susceptible an individual is to slow downs on their machine.

After settling in to OS X - which took me at least a couple of years to learn to do things based on the running of OS X and not just because I did them in Windows - if you want your Mac using a HDD running as fast as it's capable of running at all times:

1. do not install an anti-virus app - unless it is not a stay resident app and can be run only when you want it to run - ex. ClamXav

2. do not install "any" cleaning app (except Titanium's Maintenance or Onyx)

3. do not allow any apps to load at start-up - except those you use all the time and you specifically want them loading at start-up - every one of them will slow down your machine to some extent

4. run the Automation tab in Onyx when you first notice some slow down - this will depend on your use, for me, it was once every 2-3 months - for my wife, it was once every 6-12 months

5. run iDefrag when Onyx doesn't take care of the issue - this one could be more detailed, but, I'll allow those that use iDefrag figure for themselves

6. do not allow your OS X partition to go below 20-25% free space - and for those that allow their HDD to get to this point - you definitely would benefit from a defrag

7. And, for the hard core only, do not permit your OS X partition to go below 35-40% free space. Once you hit around 30% free space, a defrag is not going to get your HDD running as fast as it use to. Reading and writing to that last portion of the HDD just is not going to be as fast - period. This particular item is not OS X specific - this item relates to the nature of HDDs and is the same no matter what OS you may be using.
 
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Thanks Chscag & Bobtomay for your comments and advice - I'm sure that this information will be extremely valuable to many! Dave :)
 
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Also... it's better to do the defrag procedure overnight as it can take hours to complete. And best to run the defrag program from bootable media not your hard drive, although it is possible.

I use TechTool Pro, and run it overnight as you suggest. TTP creates a bootable "eDrive" so that you can run the Optimization tools on your main drive. It also has the feature of showing you graphically how fragmented your files or drive are or is. Then you can decide if you want to run the tools or wait awhile.
 

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Most utilities such as TechToolPro, Drive Genius, iDefrag, all offer a way to use bootable media to run the de-fragmenting process. Of course now that most of Apple's latest machines are without an optical drive, it means the process will have to run from a flash drive instead.
 
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Being cheap, every couple of years I boot up from the bootable clone of my drive I've made on an external drive (using Carbon Copy Cloner in my case), erase the boot drive, then clone back. I don't feel the need to do this any more often than that.
 
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Being cheap, every couple of years I boot up from the bootable clone of my drive I've made on an external drive (using Carbon Copy Cloner in my case), erase the boot drive, then clone back. I don't feel the need to do this any more often than that.

Hi Chas_m - I'm also using CCC for cloning my year-old Macs - just have a question concerning your comments above - if a drive is cloned exactly, isn't the fragmentation that may be present on the boot drive just duplicated? And when replaced simply repeats the fragmentation? Or is there another step - just curious & still learning - thanks. Dave :)
 
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Cloning with CCC doesn't default to sector-by-sector clone, although I believe it CAN do that. What it defaults to is file copy, which effectively de-frags any fragmented files in the copy process. So the clone/reformat/clone back process should end up with a defragged drive.
 
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Cloning with CCC doesn't default to sector-by-sector clone, although I believe it CAN do that. What it defaults to is file copy, which effectively de-frags any fragmented files in the copy process. So the clone/reformat/clone back process should end up with a defragged drive.

Thanks Jake - thought that there was a logical explanation! Dave :)
 

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@Dave

Cloning with CCC doesn't default to sector-by-sector clone, although I believe it CAN do that.

That's correct, which is why you can actually make a clone with CCC to an external drive of lesser size than the one you're cloning. (As long as it's large enough to hold the data being cloned and the small recovery partition.)

Windows cloning software such as Norton Ghost and Acronis True Image can do an uncompressed sector by sector copy or clone which requires cloning to media of the same size as the drive or partition being cloned.

BTW, I didn't know CCC could do a sector by sector clone.
 
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That's correct, which is why you can actually make a clone with CCC to an external drive of lesser size than the one you're cloning. (As long as it's large enough to hold the data being cloned and the small recovery partition.)

Windows cloning software such as Norton Ghost and Acronis True Image can do an uncompressed sector by sector copy or clone which requires cloning to media of the same size as the drive or partition being cloned.

BTW, I didn't know CCC could do a sector by sector clone.

Thanks Chscag for the additional comments! I was reading some of the excellent documentation on the CCC website, and some information quoted below from HERE - assume the statement in bold, i.e. 'block level clone' is the same as sector copying? Dave :)

I want to defragment my hard drive
A welcome side-effect of cloning one volume to another is that the files on the resulting volume are largely defragmented. While fragmentation is not as significant of an issue as it used to be (e.g. in the Mac OS 9 days), people that have begun to fill the last 10-15% of their boot volume may see some performance benefit from defragmentation. If you find yourself in this situation, this is also a really good time to consider migrating to a larger hard drive altogether.

Defragmentation is a natural result of backing up your data to an empty backup volume. Simply prepare your backup volume for use with Carbon Copy Cloner, then use CCC to clone your source volume to your destination volume. Note that a block-level clone would actually preserve fragmentation, so don't choose a block copy if you're looking to defragment your source volume.
 

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