IT新闻集锦(4)

Tiered Storage

Tiered storage is the assignment of different categories of data to different types of storage media in order to reduce total storage cost. Categories may be based on levels of protection needed, performance requirements, frequency of use, and other considerations. Since assigning data to particular media may be an ongoing and complex activity, some vendors provide software for automatically managing the process based on a company-defined policy. As an example of tiered storage, tier 1 data (such as mission-critical, recently accessed, or top secret files) might be stored on expensive and high-quality media such as double-parity RAIDs (redundant arrays of independent disks). Tier 2 data (such as financial, seldom-used, or classified files) might be stored on less expensive media in conventional storage area networks (SANs). As the tier number increased, cheaper media could be used. Thus, tier 3 in a 3-tier system might contain event-driven, rarely used, or unclassified files on recordable compact discs (CD-Rs) or tapes.

Grid Storage

Grid storage is a general term for any approach to storing data that employs multiple self-contained storage nodes interconnected so that any node can communicate with any other node without the data having to pass through a centralized switch. Each storage node contains its own storage medium, microprocessor, indexing capability, and management layer. Several topologies have been designed and tested, including the interconnection of nodes in a hypercube configuration, similar to the way nodes are interconnected in a mesh network. Grid storage offers at least three advantages over older storage methods: higher fault-tolerance and redundancy, better performance under conditions of fluctuating load and lower cost.

分级存储

分级存储是把不同类别的数据分配给不同类型的存储介质，以减少存储成本。(数据)类别可以基于所需保护的等级、性能要求、使用频度以及其他考虑。由于将数据分配给特定介质可能是一个在行进中完成的复杂动作，有些供应商提供软件，依据(用户)公司制定的策略自动管理这个过程。下面是分级存储的例子，1级数据(如关键任务、最近访问过的或绝密级文件)可以存储在昂贵的、高质量介质(如双奇偶检测磁盘阵列)RAID(独立磁盘冗余阵列)上。2级数据(如财务、很少用的、或保密文件)可以存储在常规的存储区域网络中不太贵的介质上。随着级数的增加，可以使用更便宜的介质。因而，在分3级的系统中第3级可以包括那些事件驱动的、极少用的、或不保密的文件，它们被存储在可刻录的光盘或磁带上。

网格存储

网格存储是一个普通术语，指任何使用多个互连的自给自足的存储节点存储数据的方法，其数据不必通过中央交换机一个节点就能与任何节点通信。每个存储节点包含自己的存储介质、微处理器、编制索引的能力以及管理层。已经有几种拓扑结构被设计出来并做过试验，其中一个是以超级立方配置互连节点，与网状网络中节点互连的方式类似。网格存储比起老一些的存储方法至少有三大优点：更高的容错与冗余度、在负载波动的情况下有更好的性能、以及更低的成本。