Because we chose a two disk parity setup, the effective storage size will be close to the total of the other three devices.
因为选择安装两个磁盘奇偶校验磁盘，所以有效存储大小将接近于其他三个磁盘的总和。
2
RAID-5 and RAID-6 are more frugal with respect to storage capacity, but they typically require additional hardware processing to avoid burdening the processor with the parity calculations.
At a minimum, a RAID-Z2 setup should be configured with five drives total (two used for parity) which will leave three drives to be counted as overall storage.
RAID - Z 2安装的最低要求是应该配置5个驱动器(两个用于奇偶校验)，剩下三个驱动器全部用于存储。