Hi, Was busy elsewhere for some time. Back again. @Werner Thanx for the hints and the links. Did some reading up. Building ZFS was straightforward. No config changes necessary, no tweaking , just clone, compile and install. Just like my FreeBSD rig years ago 😉   some quirks: tarball still incompatible with kernel 6.7.x, latest git version includes it so: $ git clone ... is the way Jammy missed some "needed" package but still built and installed, Bookworm h