move zfs geli encrypt mirror to unencrypted

[xpetrl]

> xpetrl <xpetrl at beepc.ch> wrote:
> 
>> Hello,
>>
>> We have a server with 4 disks, 2 zpool are zfs mirror:
>>
>> - base system unencrypted, partitions (da*p2)
>> - data storage, geli encrypted, partitions (da*p4)
>>
>> We now want to "move" the data storage (encrypt) to unencrypted partition.
> 
> 	Do you still want the encrypted partitions ? If not the simplest
> thing to do would be to detach the encrypted devices (daNp4.eli) one at a
> time and attach the unencrypted device (daNp4) in its place, wait for the
> resilver and repeat for the other devices in the zvol.
> 

Detached one drive daNp4.eli, then I didn't found how to attach daNp4:

zpool attach encrypt 3680521480316264201 /dev/da3p4
cannot attach /dev/da3p4 to 3680521480316264201: no such pool or dataset

I could just attach (again) daNp4.eli:
zpool attach encrypt 3680521480316264201 /dev/da3p4.eli


Do I miss a step?