UUIDs on drives (was Hibernate on batery low)

[Owen Townend]

2008/8/14 Kennneth P. Turvey <kt-usenet at squeakydolphin.com>:
> On Wed, 13 Aug 2008 17:27:39 +1000, Res wrote:
>
>> On Wed, 13 Aug 2008, Kennneth P. Turvey wrote:
>>
>>>> BS.  read ubuntuforums lately? even second person has problems geting
>>>> it to work, if you really want it to work, dump ubuntus version and
>>>> use the UPSTREAMS, it works fine.
>>>
>>> Apparently this isn't a problem right now.  I can't hibernate at all
>>> now.  The only issue I can think of that might of caused this problem
>>> is that I resized some of the partitions on my hard drive the the UID
>>> of the swap partition has changed.  Now it doesn't restart from
>>> hibernation (which seems to work fine), but goes back to the login
>>> screen.
>>
>> does " free " show you have a swap ?
>>
>> (I hate how they use these uid labels, it seems to have created problems
>> for a few people from reading ubuntuforums, and in here, refer the rsync
>> thread from hrmm, 6 weeks ago(?), most other distros get along fine
>> without crap like this (maybe im just too old school, and old... I dunno
>> <G> )
>
> I prefer the old method too.  I think the problem is that many people use
> external drives now and the devices will change, so UUIDs solve the
> problem.
>
> Is this the correct reasoning?  I'm just guessing here.  Are there any
> other advantages to using UUIDs that I'm missing?
>

Hey,
 Going by previous threads discussing this there are a few other good
reasons for UUIDs too:
 - Parallelism in boot scripts means devices are not always detected
in the same order.
 - Device nodes such as /dev/sda are assigned on a first-come basis,
so disconnecting a disk bumps other devices up the numbering system.
 - Labels are not always unique, (especially for removable devices
when the default is left un-altered).

 Using UUIDs gives you an (almost - it's statistically _unlikely_ that
there'll be a clash) guaranteed unique way of identifying a particular
component be it disk, usb stick, filesystem, volume group, raid array,
etc.
 These should also be unique across _multiple_ systems so you can
assign rules for mounting your usb stick, disk or array and know that
if/when it's connected the system will deal with it the way that you
intend. This is not for security (you could deliberately cause a
clash, or even simply change the UUID especially if you have physical
and/or root access), it's for sanity.

cheers,
Owen.