I want to provide protection against data loss on my servers. Typically, I'd use hardware RAID 1 or 5, but I've been reading up on ZFS. Is it correct that ZFS itself provides RAID 1 or 5 like data protection WITHOUT needing a RAID controller card? If so, I assume a single hard drive is not enough to provide data protection since if that drive fails, all data fails, so how many hard drives do I need to be running for ZFS to provide this protection?