correct way to setup gmirror on 7.4?

[Clifton Royston]

On Wed, Apr 27, 2011 at 07:35:22PM +0000, Helmut Schneider wrote:
> Michael Proto wrote:
...
> > gmirror label -v -n -b round-robin gm0p1 /dev/ad4p1
> > newfs -U -b 32768 -f 4096 -S 4096 /dev/mirror/gm0p1
> > 
> > gmirror label -v -n -b round-robin gm0p2 /dev/ad4p2
> > newfs -U -b 32768 -f 4096 -S 4096 /dev/mirror/gm0p2
> > 
> > (then I mount /dev/mirror/gm0p1 and /dev/mirror/gm0p2 and copy data
> > from my original array to this new array)
> > 
> > Finally I insert the ad6 disk and wait for the array to sync:
> > 
> > gmirror configure -a gm0p1
> > gmirror insert gm0p1 /dev/ad6p1
> > 
> > gmirror configure -a gm0p2
> > gmirror insert gm0p2 /dev/ad6p2
....
> > 
> > GEOM: ad4: the primary GPT table is corrupt or invalid.
> > GEOM: ad4: using the secondary instead -- recovery strongly advised.
> > 
> > Am I using the correct process to create this array?
> 
> No. While this works with MBR it fails with GPT as GPT and GEOM both
> want to use the last sector of the disk.
> 
> First create the mirror and after that gpart it. It will create a
> message like
> 
> GEOM: da0: the secondary GPT header is not in the last LBA.
> GEOM: da1: the secondary GPT header is not in the last LBA.
> 
> which afaik is ignorable. At least it works fine here and I didn't find
> any caveats in the net.
> 
> Another workaround is not to mirror the disk but only slices or
> partitions.

  He is mirroring only the partitions - reread above:

  gmirror label -v -n -b round-robin gm0p1 /dev/ad4p1
  etc.

  I don't know; it looks correct to me, but I may be missing something
as I don't currently use gpart.

  -- Clifton


-- 
   Clifton Royston  --  cliftonr at iandicomputing.com / cliftonr at volcano.org
       President  - I and I Computing * http://www.iandicomputing.com/
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