I think I might have made a mistake here: A couple of years ago I set up a RAID 1 OMV for my mom's photos (my first ever use of RAID and installation of OMV - so complete newb here). I used two 1TB WD Reds back then. In the meantime the 1TB has filled up so that I bought two 4TB WD Reds (the old ones) and thought I might just extend the partition of the RAID 1, so that I end up with 5TB each. I just added them in the RAID Management, so that now my /dev/md0 shows up with a capacity of 931.39 GiB, but all four physical harddrives (sda, sdb, sdc, sdd). When going to the file system, I cannot "resize" the md0, though, as it will stick with the smaller harddisks, i.e. the 1TB ones.
What is now the way to go for me? Should I go with another RAID config, e.g. RAID 10? What is probably the easiest way to achieve that? Do I have to backup all the data externally and remount all drives?
Thanks for your help!