RAID1 with gmirror

Chris Elsworth chris at
Mon Oct 11 06:26:13 PDT 2004

On Mon, Oct 11, 2004 at 12:25:46AM +0200, Christian Hiris wrote:
> > 4) bsdlabel -e ad0 [taking into account the new 16 byte offset]
> I never read about the new offset - until now I had no time to study the 
> gmirror code. Where did you find this interresting information?

Here (and related thread):

> An example in 'man gmirror' describes how to set up a gmirror array on a disk 
> with valid data. It uses 'gmirror lable' w/o extra labeling. I understand it 
> the way that the term 'valid data' means 'existing (non-gmirror-)data on an 
> already (before-gmirror-)labeled disk'. Maybe my understanding is wrong and 
> you gave me the hint to the reason why my mirrors break on startup. I will do 
> some testing on this.

No, I get the mirrors breaking on startup too. I believe this is fixed
in -CURRENT but is pending a MFC into RELENG_5 to fix.

So, I'm left quite unsure whether the warnings are harmless or not.
Pawel, can we just use existing labels on disks and apply a gmirror
over it, or should we be re-labelling inside the mirror device?


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