Adaptec 3210S User Guide - Page 122

Adaptec Storage Manager Pro User's Guide The partitions discussed here are not the same as partitions created by an operating system. Operating system partitions are subsets of the logical space presented to the operating system by the array. Redundancy Redundancy refers to the capability of preventing data loss if a drive fails. Some array types give you this capability in one of two methods: I Two identical copies-Data is written on two disk drives, resulting in the same data being stored in two places. Mirror sets, for example, use this method. I Parity-Error checking information is distributed across partitions on three or more disk drives. The error checking information permits the system to rebuild the data if one drive fails. RAID 5 sets, for example, use this method. Arrays An array is two or more physical drives grouped together to appear as a single device (logical drive) to the user. Also known as a container. A volume set created on a single disk is also referred to as an array. You create arrays on two or more physical drives. An array that spans multiple physical drives can be larger than any one of the physical drives. An array's underlying partitions can be smaller than a physical drive. Consequently, several arrays' partitions can reside on a single physical drive. The partitions that make up an array represent used (or allocated) space on each drive. The used space is available to store data, but cannot be allocated to another array. A-4