zpool labelclear destroys GPT data

[John Baldwin]

On Friday, June 14, 2013 4:21:08 am Daniel O'Connor wrote:
> 
> On 14/06/2013, at 17:48, Alban Hertroys <haramrae at gmail.com> wrote:
> > IMHO it would be helpful to verify what's there first and warn the user 
about it if such an operation will overwrite a different type of label than 
what is about to get written there.
> > Perhaps it should even refuse to write (by issuing an error stating that 
there is already a label there - and preferably also what type) until the 
label that's already there gets explicitly cleared by the user or until the 
command gets forced.
> > Does that make sense?
> 
> The problem with this is that then each label tool needs to know about every 
other label format you want to detect for..
> 
> If a label format has a checksum then you could ignore a request to nuke the 
label if there is no valid checksum (with a flag to force). No idea how many 
have checksums though..

Well, you could have zpool check if there is a valid ZFS label and prompt/warn 
if it doesn't find one on whatever device it's about to wipe.  That doesn't 
fix the gmirror/gpt case, but it might make zpool more intuitive to use.

-- 
John Baldwin