Creating vinum RAID 1 on place

[John Nielsen]

On Friday 07 July 2006 08:04, John Nielsen wrote:
> On Friday 07 July 2006 00:29, Olivier Nicole wrote:
> > Is there a trick on the way to build a vinum RAID 1 without backup-in
> > the data first?
> >
> > I have the two disk that will get mirrored. One of the disk if
> > formated as UFS 4.2 and already holds all the data. The second disk is
> > blank.
> >
> > NormallyI should start with 2 blank disks, label them as vinum, create
> > the vinum plex, then push the data on that RAID. Is there a way to do
> > it without blanking both disk first (a RAID 0 on a single disk, copy
> > the data on the RAID 0), label the other disk as vinum and create a
> > RAID1?
>
> This is quite possible.  The 100% safe way would be to configure the blank
> disk as the sole member of a (degraded) mirror set, use dump / restore to
> transfer the data from the existing filesystem to the "mirror", then wipe
> the old filesystem and add the original disk to the mirror.
>
> The faster but only 90% safe way would be to "gmirror label" the partition
> containing the existing filesystem and then adding the second disk as a
> member. This is not safe if the last sector of the existing provider (where
> gmirror stores its metadata) is (or could be in the future) used by the
> filesystem. Frequently the geometry works out such that there are spare
> sectors at the end of a partition that are not used by newfs, but if you're
> not sure then don't go this route. See the archives of this and other lists
> for details about this situation.

Sorry, I completely missed the "vinum" in your message the first time through. 
My comments above apply to GEOM mirroring (gmirror) and not to vinum. I would 
recommend gmirror over vinum for RAID 1, though, as it's much simpler to get 
going and at least as robust.

JN