A-4Adaptec Storage Manager Pro User’s GuideThe partitions discussed here are not the same as partitions createdby an operating system. Operating system partitions are subsets ofthe logical space presented to the operating system by the array.RedundancyRedundancy refers to the capability of preventing data loss if a drivefails. Some array types give you this capability in one of twomethods: Two identical copies—Data is written on two disk drives,resulting in the same data being stored in two places. Mirrorsets, for example, use this method. Parity—Error checking information is distributed acrosspartitions on three or more disk drives. The error checkinginformation permits the system to rebuild the data if one drivefails. RAID 5 sets, for example, use this method.ArraysAn array is two or more physical drives grouped together to appearas a single device (logical drive) to the user. Also known as acontainer. A volume set created on a single disk is also referred to asan array. You create arrays on two or more physical drives.An array that spans multiple physical drives can be larger than anyone of the physical drives. An array’s underlying partitions can besmaller 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, butcannot be allocated to another array.
