Defrag on a Mac

Ronald Epstein · 02-16-2008, 05:17 PM

Having problem doing any defrag on my Mac (bootups are very
slow on my Macbook Pro) and I *think* I have figured out why....

Every software I have tried (Drive Genius/TechTool) is not
allowing a defrag to be done from within the Macintosh HD.

In other words, I think I have to install these programs and run
them from a external drive and/or bootup CD so I am not doing
a defrag from within the same hard drive.

Can anyone confirm if this is true or have I just made up a
bunch of horse shit?

Thanks!

**HTF Ads**

JeremyErwin · 02-16-2008, 07:27 PM

That's pretty much it-- you can't defrag the disk without unmounting it, and you can't unmount it if it's currently hosting the active System. I generally boot from an external hard drive, but I've also used firewire target disk mode.

Ronald Epstein · 02-17-2008, 03:45 AM

Jeremy,

How can I boot from an external hard drive? SuperDuper has backed
up my entire system to an external so I can easily boot from it.

JeremyErwin · 02-17-2008, 08:40 AM

Quote:

Originally Posted by Ronald Epstein

Jeremy,

How can I boot from an external hard drive? SuperDuper has backed
up my entire system to an external so I can easily boot from it.

System Preferences/Startup Disk

Michael_K_Sr · 02-17-2008, 11:31 AM

Connect the hard disk, restart the machine and hold down the OPTION key to select which volume to boot from.

JohnRice · 02-17-2008, 11:43 AM

Isn't Tech Tool on a bootable disc? I have always found it best to boot from that disc to do the defrag. Just hold down the "C" key during startup. Of course, I haven't had Tech Tool in years, so it may not be bootable anymore. Otherwise, either of the two previous suggestions will work.

Carlo Medina · 02-17-2008, 08:17 PM

One interesting thing: I recently upgraded my MBP internal HD, and used Carbon Copy Cloner to do it. I first put in my new HD in an external drive, CCC'd to it, and then installed it.

One thing I noticed: when CCC copied everything, it did so in a logical order (system files first, program files, then music/movie files), and it defragged in the process (by nature of the HFS+ file system). I confirmed this by running the demo version of iDefrag which at least lets you analyze the fragmentation on your HD. My old HD was horribly fragmented (I do a ton of small to medium file add/deletes) and the same files on my new HD were not fragmented.

Now what I have to figure out is, next time I need a defrag, can I CCC to an external drive, boot from the external drive, and CCC back to the internal drive?

Anyone had luck with this?

JohnRice · 02-17-2008, 08:36 PM

I had terrible problems booting from any CCC backup (and just general problems), but have never had a single problem booting from a firewire backup done with SuperDuper. Never tried it with a USB drive. Now, that is my standard practice. I backup to a firewire drive, which is left off the rest of the time for added protection. When I get a new drive or just reconfigure things, I boot from the firewire drive and back it up to an internal.

DaveF · 02-18-2008, 08:05 AM

Is defragging necessary or even useful on a Mac?

On Windows, it's almost spiritual ritual for exorcising computer demons -- if anything weird is going on, do a defrag. So is defragging a Mac good practice? Or is this Windows users bringing bad habits to the Mac world?

JeremyErwin · 02-18-2008, 08:49 AM

Quote:

Originally Posted by DaveF

Is defragging necessary or even useful on a Mac?

Not Really, no. Diskwarrior is more useful for fixing the broken file systems that Disk First Aid can't handle.

Carlo Medina · 02-18-2008, 12:57 PM

Most people say no. I can, from firsthand experience, tell you that there are certain circumstances when it's useful. Here was my experience:

1. HD was over 90% full
2. Perform a lot of write, modify and/or deletion of small to medium files (i.e. AAC files 8-15MB, video files 60-600MB)
3. Have a lot of programs which constantly upgrade (4 major browsers, Adobe CS3 premium, Office 2004, iWork 06 then 08, iLife 06 then 08, ProTools 7.0-7.3.1). I upgrade my programs to the latest versions all the time.

Towards the end my HD was just slow. Spinning beach ball all the time, the startup time which had been under 30 seconds now was well over a minute.

I loaded the trial version of iDefrag which showed massive fragmentation all over the HD.

I CCC'd to a larger HD, which now is about 60% full as opposed to 93% full. I watched the CCC process and how it copied the files, I can't swear 100% it went this way as I wasn't taking notes, but it seemed to copy system files first, then the program files, then the media/personal files.

When I installed and booted up on the new HD, it was an improvement as if I had just turned on the Mac for the first time. Booted in 25 seconds, no spinning beach balls, increased load performance all across the board (more than what could be accounted for even given the fact that my new HD was 7200rpm and my old one was 5400).

Ran iDefrag, and there was almost no fragmentation. So I can say that there is a condition where defragging will help, but it is pretty extreme compared to when it's needed in Windows.

DaveF · 02-18-2008, 01:05 PM

Gotcha.

So in two years when my MBP is out of warranty, I can crack it open, add another 2GB of RAM, upgrade to a 500 GB laptop drive, and defrag too. That'll be a good spring cleaning and system refresher.

ErichH · 02-18-2008, 01:26 PM

Quote:

Originally Posted by JeremyErwin

Not Really, no. Diskwarrior is more useful for fixing the broken file systems that Disk First Aid can't handle.

Agree - the old days of defrag (any one remember the Norton nightmare?) are gone for the most part.
Best to use DWarrior on a regular basis, and perhaps a bi yearly or once a year low level format & build from scratch with a fresh backup on hand (SuperDuper is nice)