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HP StorageWorks products for small and medium-size businesses include a complete line of disk systems and modular SAN array (MSA) systems, designed to achieve greater agility for changing business needs. Storage requirements have evolved beyond the type and capacity of drives attached to a single server. As a result, the need for a high-speed connection between servers and storage devices has become critical to business performance. Storage solutions that are designed to meet these requirements include the following:
The key features of DAS, NAS, and SAN, are shown in Figure 12-1. Figure 12-1. Comparison of storage solutions.12.1.1 Direct-Attached StorageA DAS solution consists of an open-system server running any customer application and with dedicated internal or external storage subsystems using the SCSI protocol. This type of technology provides dedicated storage for multiple clients with a one-to-one server-to-storage ratio. DAS offers the easiest way to deploy incremental amounts of storage as needed without extensive upfront planning. Because RAID inside the server is becoming less expensive, DAS is growing in popularity. Currently more than 70% of all storage deployed is DAS. Smart Array controllers in a DAS configuration provide the ideal platform for high-performance applications such as databases, e-mail and messaging, and other applications that benefit from high I/O performance. Advantages of DAS include the following:
Although many customers currently have separate storage systems with storage management software products that are connected to individual servers, this strategy produces islands of data dispersed throughout a distributed IT environment. Disadvantages of the DAS method include the following:
12.1.2 Network Attached StorageNAS servers are self-contained, intelligent devices that attach directly to your existing LAN. A file system is located and managed on the NAS device and data is transferred to clients over industry-standard network protocols using industry-standard file-sharing protocols. This intelligence on the NAS device enables true data sharing among heterogeneous network clients. 12.1.3 Storage Area NetworkA SAN solution can be described as open-system servers running customer applications on an open operating system. The solution includes shared external storage resources, network infrastructure components (Fibre Channel hubs and switches), and value-added software for enhanced storage and data management. This technology provides consolidated and virtualized storage with massive scalability and fault tolerance. 12.1.4 HP Enterprise Network Storage ArchitectureENSA brings SAN, NAS, and DAS together in an architecture that meets enterprise storage requirements. Described as storage virtualization, ENSA products create pools of virtual storage from local or remote physical disks. These scalable storage pools offer flexible capacity to applications, and hardware and software fault-tolerant technologies maximize availability of the storage pool. Note For more information on HP StorageWorks products, visit http://h18006.www1.hp.com/storage/arraysystems.html. |
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