Disk fragmentation

[Charles Martin]

> From: csearles at t-online.de (Chris Searles)
>> The only exception is
>> that they don't recommend using PlusOptimizer on disks where 
>> journaling
>> is turned on. What the heck is "journaling"?
>
> As an even more general question: I've read a couple of times that Mac 
> OS X
> volumes don't even require "optimizing" in the same way that volumes 
> under
> prior Mac OS systems did. Something about UNIX taking care of such 
> problems
> by itself. Can anyone else on the list confirm this?

Going for a twofer!

1. Journaling is a UNIX trick. It makes the hard drive keep a written 
log of all the changes that have been made. This prevents directory 
corruption since the system compares its records and correct anamolies 
automatically. There's a lot more to it than that, but that's 
essentially it. It's built-in but deactivated on current Mac OS X 
10.2.x volumes. It is claimed that using it produces a small 
performance hit, which makes sense to me. Might be unnoticeable to all 
but the savviest users.

2. Mac OS X volumes can and should be defragmented periodically. If 
this were a "pure" UNIX OS, it would use UFS or some other filesystem 
and the problem of fragmentation would be reduced. However, as we still 
use HFS+ as the default filesystem, we still get disk fragmentation. 
It's not anywhere near as big a deal as most people make it out to be 
... defragging once every couple of YEARS (or after every MAJOR system 
upgrade) would be sound advice for most "normal" users. Audio/Video 
people, Photoshop pros and other people who use large chunks of disk 
space frequently would likely want to defrag more often.

_Chas_

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