The Research And Implementation Of A Multipath Technology In Storage System

With the progress of information technology and the large scale application of Internet, the amounts of data have been substantially increased, which brings a large pressure on network transport. As the extending of the network storage system, there are more and more complicated network links, so the research to improve the performance by utilizing the links is valuable and has great application foreground.To use the network link resource, building a multipath storage system platform to research the multipath technology. It's found that building the multipath module in block layer of I/O function stack has least coupling with the other modules in operation system, so bringing forward schedule algorithm using system resource can reduce the utilization factor of system resource, and is also useful to implement the flexible configuration and scalable function. By researching the virtualization technology, the way to implement the multipath virtualization is put forward, which involves adding the abstract layer to denote the virtual device and path group to implement unified management for the links and layered accessing, building the relative mapping relationship, and integrating the communication advantage of callback function, sharing memory and message mechanism to avoid the synchronization problem. By researching the error detecting technology, putting award a method that considering the network flux to forecast the next beat heart arriving time, which has made the error detecting more correct and faster. By studying the loading balance technology and different schedule strategies, it's found that three kinds of strategies can apply to the multipath module to partake the transport task, and all the strategies are effective and simple. The four strategies involves round robin, least I/O, least block, failover.With analyzing and testing to compare performance between multipath and single path, the experiment result is coordinated with the theory analysis. The multipath performance is higher that the single path. But the performance increment is reducing as the link number increasing because of the cost increasing caused by I/O redirection as the same time. So it is necessary to deep research.