I've got ubuntu server on my "home server" with 5 software raid 0 partitions and one software raid 1. I have to reinstall OS. Is it possible to do that without losing existing partitions with data?
Yes. Make sure you use the “server” installer (the “desktop” installer doesn't support RAID). Since you're reinstalling, you'll presumably want to overwrite the existing root volume, but you can retain all other volumes (just make sure to specify that you don't want to reformat these — or if the installer doesn't give you the option (IIRC it does), don't tell it about these volumes and add them to