installed Ubuntu 20.04 with ZFS enabled, want to add another SSD to pool

I Installed ubuntu 20.04 with the ZFS experimental option enabled, indeed under disks and gparted I can see that most of my current SSD is occupied by a ZFS_member.

I have very minor experience with ZFS. I set up my zfs in a previous ubuntu 18 install but the OS itself was not on ZFS.

anyways : How do I add another SSD (not the same size or brand) to my current ZFS pool?

I just want the most basic "add space" I don't really care about x2, x3 or x10 redundancy (in fact I don't want to alter current ZFS redundancy setup, whatever it is). I just want extra space.

I found this : https://unix.stackexchange.com/questions/530968/adding-disks-to-zfs-pool

but it doesn't answer my question for someone of my level.

For example none of the two people who answered specified if it was :

zpool create addonpool /dev/sdb
zpool add addonpool mirror /dev/sda /dev/sdb

Or just :

zpool add rpool mirror /dev/sda /dev/sdb#"rpool" name of existing pool, apparently

Nor what syntax is used to point to drives.

I want to expand rpool

all the links I found are referencing syntaxes like : c0t3d0, c1t3d0, and c1t1d0.

I can't find such an identifier, this guide : https://www.thegeekdiary.com/zfs-tutorials-creating-zfs-pools-and-file-systems/ uses echo | format this does not work in ubuntu 20.04

I do know their guid :

t@tsu:~$ sudo lshw -class disk
[sudo] password for t: 
  *-disk:0                  
       description: ATA Disk
       product: Samsung SSD 850
       physical id: 0
       bus info: scsi@2:0.0.0
       logical name: /dev/sda
       version: 2B6Q
       serial: S2RBNX0J524197X
       size: 465GiB (500GB)
       capabilities: gpt-1.00 partitioned partitioned:gpt
       configuration: ansiversion=5 guid=32f4df93-2b50-4a68-a888-f0570adac413 logicalsectorsize=512 sectorsize=512
  *-disk:1
       description: ATA Disk
       product: Crucial_CT525MX3
       physical id: 1
       bus info: scsi@4:0.0.0
       logical name: /dev/sdb
       version: R040
       serial: 172918010661
       size: 489GiB (525GB)
       capabilities: gpt-1.00 partitioned partitioned:gpt
       configuration: ansiversion=5 guid=d3e2b4ab-2c44-4da8-ac0c-fdb8053d35da logicalsectorsize=512 sectorsize=512

I did test just zpool alone to get the man, this works so I know that I'd be able to run the above I just want to not mess it up.

Also I'm planning on doing this by logging out and running my commands in a tty. It does nag me that technically at such a point I have not really exited the environment using my ZFS pool so will that work or should this be done from a Live USB?

t@tsu:~$ zpool status
  pool: bpool
 state: ONLINE
  scan: none requested
config:

    NAME                                    STATE     READ WRITE CKSUM
    bpool                                   ONLINE       0     0     0
      73ea4055-b5ea-894b-a861-907bb222d9ea  ONLINE       0     0     0

errors: No known data errors

  pool: rpool
 state: ONLINE
  scan: none requested
config:

    NAME                                    STATE     READ WRITE CKSUM
    rpool                                   ONLINE       0     0     0
      7905bb43-ac9f-a843-b1bb-8809744d9025  ONLINE       0     0     0

errors: No known data errors

    t@tsu:~$ blkid
    /dev/sda2: UUID="53c19176-f03e-4c40-a6ed-3a2627160647" TYPE="swap" PARTUUID="7a5a6a79-1359-e04f-a783-1845b8bff78f"
    /dev/sda1: UUID="3B30-7656" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="f1ae5c48-1ad3-4aff-9161-f0379f64d556"
    /dev/sda3: LABEL="bpool" UUID="3543073794614485280" UUID_SUB="6877096781256962450" TYPE="zfs_member" PARTUUID="73ea4055-b5ea-894b-a861-907bb222d9ea"
    /dev/sda4: LABEL="rpool" UUID="9443649997029540364" UUID_SUB="15472508558080641563" TYPE="zfs_member" PARTUUID="7905bb43-ac9f-a843-b1bb-8809744d9025"

t@tsu:~$ zfs list
NAME                                               USED  AVAIL     REFER  MOUNTPOINT
bpool                                              442M  1,32G       96K  /boot
bpool/BOOT                                         440M  1,32G       96K  none
bpool/BOOT/ubuntu_38tazy                           440M  1,32G      178M  /boot
rpool                                              169G   276G       96K  /
rpool/ROOT                                        8,66G   276G       96K  none
rpool/ROOT/ubuntu_38tazy                          8,66G   276G     3,65G  /
rpool/ROOT/ubuntu_38tazy/srv                       152K   276G       96K  /srv
rpool/ROOT/ubuntu_38tazy/usr                       480K   276G       96K  /usr
rpool/ROOT/ubuntu_38tazy/usr/local                 384K   276G      128K  /usr/local
rpool/ROOT/ubuntu_38tazy/var                      3,17G   276G       96K  /var
rpool/ROOT/ubuntu_38tazy/var/games                 152K   276G       96K  /var/games
rpool/ROOT/ubuntu_38tazy/var/lib                  3,10G   276G     2,53G  /var/lib
rpool/ROOT/ubuntu_38tazy/var/lib/AccountsService   464K   276G      112K  /var/lib/AccountsService
rpool/ROOT/ubuntu_38tazy/var/lib/NetworkManager   2,37M   276G      208K  /var/lib/NetworkManager
rpool/ROOT/ubuntu_38tazy/var/lib/apt              75,1M   276G     65,6M  /var/lib/apt
rpool/ROOT/ubuntu_38tazy/var/lib/dpkg             97,3M   276G     38,1M  /var/lib/dpkg
rpool/ROOT/ubuntu_38tazy/var/log                  69,7M   276G     34,5M  /var/log
rpool/ROOT/ubuntu_38tazy/var/mail                  152K   276G       96K  /var/mail
rpool/ROOT/ubuntu_38tazy/var/snap                 1016K   276G      160K  /var/snap
rpool/ROOT/ubuntu_38tazy/var/spool                 512K   276G      112K  /var/spool
rpool/ROOT/ubuntu_38tazy/var/www                   152K   276G       96K  /var/www
rpool/USERDATA                                     160G   276G       96K  /
rpool/USERDATA/root_mh3805                         956K   276G      208K  /root
rpool/USERDATA/t_mh3805                            160G   276G      142G  /home/t