FreeBSD 9/ZFS: Striped Pool (2 disks) migrating to mirror (onto additional disk)

Christer Solskogen christer.solskogen at
Wed Jan 26 20:47:36 UTC 2011

On Wed, Jan 26, 2011 at 9:42 PM, Dan Nelson <dnelson at> wrote:

> ZFS lets you add and detach mirrors on the fly, since you're not changing
> the capacity of the pool itself.  Sure, you're going to lose the contents of
> the large 2TB drive, but that's sort of assumed.  You can't convert 4TB of
> non-mirrored disks into 2TB of mirrored disks without losing 2TB of space.
> Just make sure you have less than 2TB total used data on all volumes, and
> copy the data off the 2TB filessytem onto the striped 1+1TB one before
> repartitioning and adding the mirrors.
>  zpool attach [-f] pool device new_device

The problem is that you cant attach a drive to a vdev that consists of
two striped disks.


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