ASM Mirror Waste

Does anyone use ASM Normal Redundancy with large LUN such as 1TB?

We are considering use 1TB LUN for a 6TB Database but when normal redundancy is used ASM reserves 1 LUN space (distributed in all LUN) to avoid mirroring failure so we will lose 1TB when use 1TB LUN or 2TB if we use 2TB LUN. When we try to allocate more space then we will hit ORA-15041 space exhausted. It works like a RAID 5 with a hot spare disk. Sort of a Waste.

Does anyone know if there are anyway to bypass ORA-15041 error? In our case if we lose a disk we really dont care if one side of mirror dies.

TIA

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