| In recent years, along with the rapid development of network technology, coincided with the progress of science and business, Internet data shows exponential growth trend, so more and more data need distributed storage. In order to improve the response speed, a distributed system has to maintain multiple copies of data object to deal with concurrent request. Data replication technology is important technology to improve data availability and capability of access, but the consistency maintenance become to the new problem. Based on this, a eventually consistency strategy based on gossip system structure was proposed. Considering with data organize, update broadcasting, update performance, the new strategy makes the big sense on the management mode of the copies, updating content, transmission mode, concurrent control and the exception handling.The new strategy uses "the home" management mode, a derivative version of traditional "master-slave type" management methods. This can avoid the bottleneck of update receiving in the traditional "master-slave" management method; maintain the whole sequence consistency as well.Copy manager is the core of gossip system structure, using vector timestamp way to manage data timing state, recording and broadcast update semantics with update log. Compared with the traditional gossip system structure, the new strategy bring in some statistics of update log and copies state to improve broadcast mode, using anti-entropy as the transfer mode, by contrasting the statistical information, log redundant is avoided. Meanwhile, in the conversation object selection algorithm aspect, the strategy also made improvements. To fit the centralized mode of update submitting and the peer-to-peer mode of update accepted, the new strategy promotes the speed of update broadcasting. Work with the log cutting algorithm, the system can delete the log in time, which is overtime. So the disk space of the chunk server will be kept in a reasonable scale. The ratio of the space utilization becomes much higher. |
