@NikosAlexandris I just spent ten minutes staring at that page, and finding LVM doc that is linked (since the link doesn't work...) and I can confidently say: I have no clue where you put that script fragment.
Glad to hear you got something (ZFS) working, though...
@NikosAlexandris If you click on the little arrow to the left of the message, it'll show you which message its a reply to—in this case, some "Activating RAID device" script you posted