摘要:
在大规模分布式存储系统的容错技术中，数据副本管理是一种重要机制.针对网络环境中的动态副本管理需求，建立一种文件支持度指标及其动态计算模型.该模型通过周期性数据采集，利用文件支持度的自相关性，结合文件上一采集周期访问量、访问量占比、被访问数据量以及文件级别等参数，构建了能够较准确描述文件的动态副本需求状态模型.通过动态适应性的参数调整以适应变化的负载状态，使副本管理决策尽可能反映系统实际状态.在此基础上设计了数据结点负载均衡、副本调整、副本清理等相关算法，实现了动态副本管理的目标.通过实验验证了所设计的动态副本管理机制的有效性.
Abstract:
Replication-based management schema is an important fault tolerance mechanism in large scale distributed storage systems. In response to the demand of dynamic replication management in distributed storage systems, a file popularity index named file support degree and its computation model are proposed. Within this model, file’s parameters are periodically collected. By combination of self-correlation of file support degree, file hits in previous collection cycle, accessed data volume and file’s grade, a model that exactly reflects files’ replication requirement is built. To adapt to the variable system load, the model dynamically adjusts its parameters, making the replication decision-making to reflect real system status. Based on these work, some algorithms like load balancing, replication adjustment and replication clearing are designed. To avoid a single data storage node being overloaded, a data storage nodes’ load-balance strategy is proposed. In this strategy, data storage nodes are divided into 3 groups: a holding group, an acceptable group and a begging group. There are 2 periodic procedures in the system, including replication adjusting procedure and replication clearing procedure. In replication adjusting procedure, top P files are replicated to data storage nodes selected based on the load-balance strategy. Replication clearing procedure is a long-periodic procedure, because it needs many adjusting procedures to make the begging group be empty. This dynamic replication management mechanism is proven effective through the given experimentations.
百度学术
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