glabel, gpart and zfs confusion.

[Jason Hellenthal]

On Sat, Feb 25, 2012 at 09:42:08AM +0100, Peter Ankerstål wrote:
> Hi,
> 
> Now Im really confused. 
> 
> I want in some way label my drives so the setup is independent of physical setup. But Jason doesn't
> seem to like glabel at all. :D
> http://lists.freebsd.org/pipermail/freebsd-fs/2012-January/013574.html
> 
> And then he says that you should use gpart instead
> http://lists.freebsd.org/pipermail/freebsd-fs/2012-January/013578.html
> 
> But this seems to be in conflict with the common knowledge that zfs should
> be used on whole disks, not partitions!
> 
> Any pointers? 

glabel(8) Is not known by any other system than FreeBSD. GPT or that
createed by gpart(8) are.

For clarity say you create a label "test01" for /dev/ad0, you then
create a ZFS pool upon "/dev/label/test01". For some reason or months
down the road you somehow disable glabel on the system and boot... ZFS
will search for the pool within the actual disks ultimately erasing your
precious glabel.

Another instance I have seen is people booting a live Solaris disc to
repair the likes of anonymous "bad things". They find out that coming
back to FreeBSD that the label is now gone. Now if you try to
re-glabel(8) that disk that contains ZFS would you be absolutely
confident that it is NOT overwriting anything important ?

This is why I do not like generic labels they are a good idea but they
are only temporary and very fragile when it comes to the above
instances.

ZFS on Solaris by default creates pools on a partition that spans
accross the "whole disk". They are not refering to using the raw disk
though you certainly may if thats what tweaks you. This is often
confused.

Hope this helps.

-- 
;s =;
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