Replace single disk RAID0 to JBOD

deb http://hwraid.le-vert.net/debian stretch main

#install dirmgr
apt-get install dirmngr

#add key
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6005210E23B3D3B4

apt-get update && apt-get install -y megacli

#turn on JBOD
megacli -AdpSetProp EnableJBOD 1 -a0

#detach disk
zpool detach rpool /dev/sdb2

#backup disk structure
sgdisk --backup=disk /dev/sdb

#remove drive 1
megacli -CfgLdDel -L1 -a0

#create JBOD device
megacli -PDMakeJBOD -PhysDrv[252:1] -a0

#load disk structure
sgdisk --load-backup=disk /dev/sdb
sgdisk -G /dev/sdb

#copy EFI
dd if=/dev/sda1 of=/dev/sdb1 bs=512

#or copy MBR
dd if=/dev/sda of=/dev/sdb bs=512 count=1

#attach disk to mirror
zpool attach rpool /dev/sda2 /dev/disk/by-id/wwn-aaaaa-part2