Disable RAID auto detect at runtime

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http://unix.stackexchange.com – In Linux, I'm partitioning two disks for RAID1 with fdisk. The first disk partitioning succedes, but the second fail because the raid starts automatically and occupy also the second disk (why? it should have a different UUID). How to temporary disable RAID autodetect? I guess there's a switch under /proc/sys filesystem. I know it's possible to solve the problem in other ways, like removing RAID information from the disks with mdadm --zero-superblock but I want to know if it's possible to disable RAID autodetect without rebooting the system with raid=noautodetect nomdadm in kernel parameters. (HowTos)