I wish to reformat my HDDs (2x 1 TB WD) from the OS Extended (Journaled) format to the new APFS, and to make a stripped RAID with these disks. One of these disks is currently my boot drive. The machine is the Mac Pro 5,1 Tower (not a flashed 4,1), running High Sierra. Blackmagic shows that I currently get about 40 MB/s read and write on these old SATA drives, and expect the conversion to give me at least a doubling of this dismal speed (not much, I know, but until I can afford a PCIe SSD this will have to do). I need to know the best fail-safe way to make this migration, bringing over both the data files and software from my Timemachine backup. Some of my software is not available for re-installation which would be required if, for some reason, this migration fails. Hence I am a little hesitant to reformat my boot drive until I know that this can be done successfully. Please advise (and reassure) me.