Research On Consistency Of Distributed Storage TDCS/CTC Data Based On Paxos Algorithm

The data of train operation dispatching command system/centralized traffic control(TDCS/CTC) data plays an important part in vehicle running safety, which is analyzed and statisticed by working staff to provide the convenient and reliable basis for fault analysis and scene reappearance. However, most of the present data storage technologies have stayed at the level of dual redundancy technology and disk array technology. Therefore, the fault tolerance is poor and disk can not be restored if damaged. The data will be changed as the storage medium and other defects, resulting in low reliability of the data, backup data consistency difference. Aimed at these problems, distributed storage system and Paxos algorithm are combined to store the TDCS/CTC system data. The main contents are as follows.Firstly, by the analysis of the composition of the TDCS/CTC system hardware and the type of data, the shortage of the existing storage technology are pointed out.In order to improve the availability and reliability of the data, the distributed storage system is used to storage data.Secondly, further study of the advantages and disadvantages of distributed storage system, it is concluded that the consistency of the data is the key property of distributed storage system. According to the CAP theory, Paxos algorithm is chosen for the key algorithms to ensure data consistency and optimized to reduce algorithm of traffic.Thirdly, distributed storage system and Paxos algorithm are combined and TDCS/CTC data distributed storage model is established based on Paxos algorithm. First of all, the master node is elected based on Paxos algorithm, witch is responsible for the interaction of the client data. Secondly, the data is distributed stored in each copy of the node. Finally, Fault detection mechanism is established to assure the system to work normally.Finally, the consistency of master node and copy node are data checked. Two methods are used to realize consistency checking in the thesis, that is, the traditional consistency checking method and the consistency checking method based on summation digest. The comparison experiments show that both methods can check the consistent of data, but the consistency checking method based on summation digest could less time-consuming than the traditional.