Setting up RAID-1 on 2 unequal disks

[Tony Shadwick]

I'd say use gvinum.  It's a bit tricky....actually, it's VERY tricky. 
You have to get the geometry of the shared volume precisely right on the 
120GB drive to match the 80GB drive, then you can allocate the rest of 
the free space.

Honestly, you *could* cheat here. :)  I think....

Set up your 80GB drive.  We'll call it /dev/ad0.

Plug in your 120GB drive but don't do anything to it.  We'll call it 
/dev/ad1.

dd if=/dev/ad0 of=/dev/ad1

Now, set up gvinum as though they were of the exact same geometry, and 
get your mirror going.  Then, go back and modify the drive label of ad1, 
and allocate the rest of the space on that disk.  You'll want to have 
gotten the REAL drive geometry of /dev/ad1 ahead of time, because (if I 
recall...) you're going to have to change c: to the correct geometry, 
then add partitions using space above and beyond what you have on ad0.

Does that make sense at all?   Perhaps you should work through setting 
up a normal gvinum mirror before going this route...

Foo JH wrote:
> Hi all,
> 
> I unfortunately have 2 uneuqally sized SATA disks to set up a mirrored 
> shared folder: 80GB and 120GB. On the 120GB I plan to set up this way:
> 
> /temp        2GB (double the system memory)
> /shared    80GB
> /               38GB
> 
> I plan to mirror /shared onto the 80GB. It won't be bootable, but I can 
> always mount it onto another FreeBSD machine.
> 
> I've read some articles on mirroring on non-equal disks, notably:
> http://people.freebsd.org/~rse/mirror/
> 
> My question is: is there an easier way to do this? The example looks 
> quiet daunting for a noobie FreeBSD admin like me.
> 
> Appreciate any feedback on this. Thanks.
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