Tested on Ubuntu 20.04 VM

zfs-test.sh

root@zfsfun:/tank/test# zfs --version
zfs-0.8.3-1ubuntu12.1
zfs-kmod-0.8.3-1ubuntu12

root@zfsfun:~# zpool create tank sdb        

root@zfsfun:~# zfs create tank/test

root@zfsfun:~# cd /tank/test

root@zfsfun:/tank/test# for n in 1 2 3 4 5 6 7 8 9 ; do cp -a /boot $n & done


root@zfsfun:~# lsblk 
NAME    MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
loop0     7:0    0 27.1M  1 loop /snap/snapd/7264
loop1     7:1    0   55M  1 loop /snap/core18/1705
loop2     7:2    0 69.1M  1 loop /snap/lxd/14890
sda       8:0    0  2.2G  0 disk 
├─sda1    8:1    0  2.1G  0 part /
├─sda14   8:14   0    4M  0 part 
└─sda15   8:15   0  106M  0 part /boot/efi
sdb       8:16   0   10G  0 disk 
sdc       8:32   0   16G  0 disk 
├─sdc1    8:33   0   16G  0 part 
└─sdc9    8:41   0    8M  0 part 
sdd       8:48   0   16G  0 disk 
├─sdd1    8:49   0   16G  0 part 
└─sdd9    8:57   0    8M  0 part 
sde       8:64   0   16G  0 disk 
├─sde1    8:65   0   16G  0 part 
└─sde9    8:73   0    8M  0 part 
sr0      11:0    1    4M  0 rom  
 
root@zfsfun:/tank/test# df -h .
Filesystem      Size  Used Avail Use% Mounted on
tank/test       9.3G  638M  8.6G   7% /tank/test

root@zfsfun:/tank/test# zpool add tank raidz sdc sdd sde
invalid vdev specification
use '-f' to override the following errors:
mismatched replication level: pool uses disk and new vdev is raidz

root@zfsfun:/tank/test# zpool add -f tank raidz sdc sdd sde

root@zfsfun:/tank/test# zpool status
  pool: tank
 state: ONLINE
  scan: resilvered 4.50K in 0 days 00:00:01 with 0 errors on Fri Jun 19 09:36:55 2020
config:

        NAME        STATE     READ WRITE CKSUM
        tank        ONLINE       0     0     0
          sdb       ONLINE       0     0     0
          raidz1-1  ONLINE       0     0     0
            sdc     ONLINE       0     0     0
            sdd     ONLINE       0     0     0
            sde     ONLINE       0     0     0

errors: No known data errors

root@zfsfun:/tank/test# zpool remove tank sdb
cannot remove sdb: invalid config; all top-level vdevs must have the same sector size and not be raidz.