What techniques for disk, volume and file system management are possible with OS X, but troublesome within Disk Utility? In the past, Disk Utility was the best starting point for the vast majority of disk-related tasks. 

As technologies within (or possible with) OS X have developed – without equal development of Disk Utility – so it may be useful to have: 


a shortlist of actions that are best attempted/begun without Disk Utility. 


This question

I'd like answers to form something like: 


a shortlist of things that appear illogical or impossible in Disk Utility.


I'll seed at least one answer to exemplify what I have in mind. 

For some of the things mentioned, there will be answers elsewhere in Stack Exchange – so here, commentary may be minimal. 

Background

Maybe more noticeable with Mountain Lion than with Lion:


some capabilities that are integral to the operating system are
misrepresented or impossible within Disk Utility 
some capabilities that are added by third part software are misrepresented within Disk Utility


… and so on. 

I'm fairly familiar with routines for HFS Plus and for ZEVO implementations of ZFS. Less familiar with routines for other file systems (both native and not native to OS X). 

Recall that features such as Core Storage and FileVault 2 are relatively new, and without native support in Snow Leopard, so let's be gentle in our observations – for any peculiarity, assume that an overriding mantra of 'first do no harm' is applied by Apple. 

Beyond this question

A redesign of Disk Utility, by Apple, is desirable but that will be beyond the scope of Ask Different so please: no design suggestions here.

Discussion in Ask Different Chat


2012-07-28
2012-07-29


Additional context (November 2015)

http://forums.macrumors.com/posts/22209602 for a public record of what was originally a private enhancement request (ER), made through AppleSeed in 2012.
Things not within a logical volume group (LVG) appear to be within the LVG

Affected: some applications of Core Storage, including but not limited to FileVault 2 in Mountain Lion.

Example

Disk Utility 13 (426) in Build 12A269 of OS X 10.8: 



Volumes swap and spare are JHFS+ and truly not within the LVG. 

disk0s3 is an Apple_Journal, currently unused and truly not within the LVG.

Disk Utility misrepresents all three as being within the LVG.