HP StorageWorks Modular Smart Array 1000 HP StorageWorks 1000/1500 Modular Sma - Page 47

RAID 0-No fault tolerance A RAID 0 configuration (Figure 3) provides no protection against data loss when a drive fails. However, it is useful for rapid storage of large amounts of non-critical data (for printing or image editing, for example), or when cost is the most important consideration. Table 3 RAID 0 features Advantages Highest write performance of all RAID methods. Lowest cost per unit of stored data of all RAID methods. All drive capacity is used to store data (none is needed for fault tolerance). Disadvantages All data on the logical drive is lost if a physical drive fails. Cannot use an online spare. Can only preserve data by backing it up to external drives. RAID 1+0-Drive mirroring In a RAID 1+0 configuration, data on a physical hard drive is duplicated to a second drive. NOTE: When only two hard drives are included in the array, this fault-tolerance method is called RAID 1. When more than two hard drives are included in the array, this fault-tolerance method is called RAID 1+0. RAID 1 is not supported on the MSA1510i storage system. B1 B1 B2 B2 B3 B3 B4 B4 D1 D2 15314 Figure 5 RAID 1 array, with two physical hard drives (D1 and D2) When the array has more than two physical drives, drives are mirrored in pairs (Figure 6). S1 B1 B2 B3 B4 S2 B5 B6 B7 B8 D1 D2 D3 D4 D5 D6 D7 D8 S1 B1 B2 B3 B4 S2 B5 B6 B7 B8 15315 Figure 6 RAID 1+0 array, with eight physical hard drives (D1 through D8) HP StorageWorks 1000/1500 Modular Smart Array Command Line Interface user guide 47