some infos on the subject ** is it possible to make a btrfs add from a running root, then balance to raid 1 no problem (usual caution here) ** once done will it be possible to boot (from uefi) to any partition (sda2 or sdb2)? no my case is probably a bit special; I run a pretty large laptop with dvd writer so I removed the writer and set in place a caddy with (now) a ssd, where I installed Leap 15 nothing to notice, until I run the raid thing. main disk (also a ssd) was at start msdos formatted (due to history reason). I reformatted it as GPT now. at boot: immediately go to uefi firmware without notice. There I finally noticed the computer only sees one disk (main one), do not see the caddy disk. see also that CSM/compatibility mode was up. Removed it and now I boot with no problem my raid1 system I guess only grub on main disk starts and setting raid may have broken the fake gpt msdos entry this computer is said (by the net) to not be able to boot a hard drive from a caddy, so if the main disk fails, I may have to swap it for the caddy one to boot jdd -- http://dodin.org -- To unsubscribe, e-mail: opensuse-support+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-support+owner@opensuse.org