Martti schrieb:
There is no option for creating a new RAID1 array in manage menu, only options for modifying the existing array or marking the smallest non-raid disk as spare. The boot IRST utility is version 9.5 and does not support 3TB drives.
The missing support of >2TB sized drives will be the reason why you cannot create a RAID array with them. The IRST Console is nothing than a software, but the Intel SATA RAID Controller of your system requires an up-to-date Intel RAID ROM module, which is part of your manboard BIOS. Only Intel RAID ROM modules from v10.6 up do Support HDDs >2 TB.
Solution for your problem:
Ask your mainboard manufacturer for a BIOS with updated Intel RAID ROM or update it yourself. Here you can find a guide about how to do it: BIOS Modding Guides and Problems.