User manual HP HSC ARRAY CONTROLLER SMART ARRAY CONTROLLER TECHNOLOGY

[. . . ] HP Smart Array Controller technology technology brief Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Storage trends. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Meeting data storage requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Capacity growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Since the controller knows that the parity data is consistent with all the member drives in the stripe, the controller needs to read from only two hard drives during a RAID 5 write (or three hard drives for a RAID 6 write) to compute the parity data (regardless of array size). This technique is called a read-modify-write or backed-out writes. RAID 1 load balancing In general, RAID 0, RAID 5, and RAID 6 with ADG logical drives have the same read performance given the same stripe size and array size. RAID 1 logical drives contain two copies of the data. During reads to RAID 1 logical drives, the Smart Array controller issues read requests to either drive in the mirrored set. During a heavy read load, the Smart Array controller balances the number of requests between the two hard drives to achieve higher read bandwidth. This technique is called RAID 1 load balancing. Hardware RAID Today's operating systems offer basic RAID 0, RAID 1, and RAID 5 disk management functions, called software RAID, to create logical drives that do not contain the operating system. Software RAID requires a significant amount of the server's resources to perform management functions. Smart Array controllers offload the server by managing the array using a separate processor and memory subsystem. Furthermore, the parity calculations required by RAID 5 and RAID 6 with ADG are performed by specialized hardware engines that maximize data throughput for disk write, rebuild, and regenerate read operations. Data availability Online array expansion, logical drive extension, stripe size migration, and RAID migration provide data availability protection against planned downtime by allowing network administrators to modify the array without interrupting user access. Additional Smart Array controller features provide protection against unplanned downtime due to subsystem failure with a full-spectrum faultmanagement approach that addresses fault prediction, fault tolerance, and fault recovery with the highest levels of data availability for demanding business requirements. Smart Array controllers can monitor I/O activity, track key parameters, predict potential problems, take corrective actions, provide automatic recovery, and deliver full fault management. RAID support In 1989, Compaq (now HP) was the first company to introduce RAID subsystems in the network server marketplace with the Systempro server. Today, RAID is an industry-standard technology and most online network data storage is protected with some level of RAID. Smart Array controllers support RAID levels 0, 1, 1+0, 5, and 6 with ADG. Today, only Smart Array controllers offer RAID 6 with ADG, which provides higher fault tolerance than RAID 5 with lower implementation costs than RAID 1+0 and greater usable capacity per unit density than RAID 1. HP pioneered this technology and introduced it to the marketplace in 2001. Beginning with the SAS transition in mid 2006, other server storage providers will began to ship RAID 6 enabled products. For RAID 5, HP recommends using no more than 14 physical drives per logical drive (8 physical drives per logical drive is optimal). However, because logical drive failure is less likely with RAID 6 with ADG, HP recommends using up to 56 physical drives per drive array when running RAID 6. Using patented HP technology, administrators can safely deploy large-capacity disk drives and create storage volumes greater than 2 terabytes (TB). 11 Stripe size migration Stripe size migration allows administrators to use the ACU change the stripe size of a logical drive without planned down time. [. . . ] The program displays configuration information, operating system device driver version numbers, controller firmware version numbers, Pre-Failure Warranty information and operating statistics. Performance monitoring HP Systems Insight Manager gives administrators a window to look at low-level performance characteristics of Smart Array controllers in the environment. It monitors three basic Smart Array controller performance parameters for proactive management of the storage subsystem: · I/O commands per second · Average command latency · Local processor utilization Analyzing these key parameters can assist administrators in fine tuning configurations for performance. HP Systems Insight Manager also provides a means for graphically charting performance over time for each of these parameters. [. . . ]