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Spanning
Spanning provides another maximum capacity solution. Spanning combines multiple
hard drives into a single logical unit. Unlike Striping, Spanning writes data to the first
physical drive until it reaches full capacity. When the first disk reaches full capacity,
data is written to the second physical disk. Spanning provides the maximum possible
storage capacity but does not increase performance.
Mirroring
Mirroring (RAID 1) consists of at least two drives storing duplicate copies of the same
data. In this mode, the data is simultaneously written to two disks. Thus, the storage
capacity of a two-disk array is combined into a single disk and the capacity is limited
to the size of the smallest disk. In Mirroring mode, identical HDDs of the same
capacity and RPM from the same manufacturer are highly recommended for best
capacity utilization.
