and … in w10 ? my 1tb falied with raid on 1 2tb … and i got 1 4tb! … so … raid on 2x2tb. help 
! shall i extend the partition on the 2tb? … will the node “refresh” the “new space” available ? …hummmm 
thkz!
Do not “extend”. It will be a RAID0. With one disk failure the whole node is lost.
What do you mean by
Did you have RAID0 with 2 HDDs, each 1TB in size?
If so, if your one disk is failed - the whole node is lost. You will be forced to start over with a new identity and clean data.
Do NOT use the RAID with 2 HDD. It will be always RAID0 and whole disaster for your node, when the one of them is failed.
If you have only 2 HDD, and want to use them, you should run 2 separate node with own idenity on each of HDD. If one disk is failed, you will still have a second node.
Since you on Win10, with Windows GUI installer you can setup only one service. The recommended way for the Windows 10 and multisetup is use the Docker. It doesn’t have a such limit.
Also, you can try to use the unsupported way to setup a few nodes with a Windows GUI, some SNO have used it and shared the experience how to do it here, on forum.
Based on another topic I think it was a RAID1 that failed and perhaps failed again during resync causing actual data loss. I’m not entirely sure.
Still I agree with Alexey. By far the best thing to do in your situation is run 2 nodes on the 2 HDD’s you have. Don’t bother with RAID as the sizes of your HDD’s are relatively small and in your case actually pretty likely to fill up. You’ll make more money if you just run more than one node. Avoid using docker this time. For multiple nodes on windows GUI you can try @Vadim’s toolbox.
Though this is not an officially supported method for installing multiple nodes, I think it is probably better than using docker. Be sure to keep an eye on development progress in that topic though.